Information

International Society for Soil Mechanics and Foundation Engineering

Societe Internatianale de Mecanique des Sols et des Travaux de Fondatians

Report of the ISSMFE Technical Committee on

Penetration Testing of Soils - TC 16 with Reference Test Procedures

CPT- SPT- DP- WST

SWEDISH GEOTECHNICAL SOCIETY

SWEDISH GEOTECHNICAL INSTITUTE

PREFACE

The present report is the final document by the ISSMFE Technical Committee on Penetration Testing of Soils TC 16 which initially was appointed in 1982 and reappoinshyted in 1985 The report contains Reference Test Procedushyres for four different types of penetration testing methods (in English and French)

bull Cone Penetration Test (CPT) e Standard Penetration Test (SPT) bull Dynamic Probing (DP) bull Weight Sounding Test (WST)

According to an agreement between the International Society for Soil Mechanics and Faundatian Engineering the Swedish Geotechnical Society (as host society for TC 16) and the Swedish Geotechncial Institute (SGI) this report is published in SGI Series Information Hopeshyfully this document will be of worldwide use to people cancerned with penetration testing manufacturers conshysultants contractors field engineers researchers and students

Finally I would like to convey my sincere thanks to all the committee members for their deserving work especishyally the Chairmen of the working groups Professor E De Beer Mr S Thorburn and Dr KJ Melzer our Coshychairman Mr WJ Heijnen and our Secretary Dr E Sell shygren

Linkoumlping June 1989

Chairman of the ISSMFE Technical Committee on Penetration Testing of Soils

Ulf Bergdahl Swedish Geotechnical Institute

ISSN 0281-7578

CONTENTS

TABLE DES MATIERES

PREFACE

REPORT OF THE ISSMFE TECHNICAL TESTING OF SOILS - TC 16

COMMITTEE ON PENETRATION 2

APPENDIX A INTERNATIONAL REFERENCE TEST PROCEDURE PENETRATION TEST CPT)

FOR CONE 6

APPENDIX B INTERNATIONAL REFERENCE TEST PROCEDURE PENETRATION TEST (SPT)

FOR THE STANDARD 17

APPENDIX C INTERNATIONAL REFERENCE TEST PROCEDURES PROBING (DP)

FOR DYNAMIC 20

APPENDIX D INTERNATIONAL REFERENCE TEST PROCEDURE SOUNDING TEST (WST)

FOR THE WEIGHT 24

APPENDICE A MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

28

APPENDICE B METHODE DESSAIS DE REFERENCE DE PENETRATION STANDARD SPT)

INTERNATlONALE POUR LESSAI 39

APPENDICE C PROCEDURES INTERNATlONALEs DESSAI PENETROMETRE DYNAMIQUE DP)

DE REFERENCE AU 42

APPENDICE D REFERENCE INTERNATlONALE CONCERNANT LE MODE LESSAI DE PENETRATION PAR CHARGES WST)

OPERATOIRE DE 46

REPORT OF THE ISSMFE TECHNICAL COMMITTEE ON PENETRATION TESTING OF SOILS TC 16

l ACTIVITIES OF THE COMMITTEE ON PENETRATION TESTING

11 Activities of the subcommittee on standardization of penetration testing in Europe

At the Fourth International conference on Soil Mechanics and Faundatian Engineering in London 1957 a Subcommittee on Static and Dynamic Penetration Testing Methods was appointed to study the methods of static and dynamic penetration tests with a view to their standardization

Between the years 1957-1961 the various methods were studied and comparative analyses were carried out However the Subcommittee did not make any recommendations to the Executive Committee at the Fifth International Conference in Paris 1961 It was decided that the work of the Subcommittee should be continued with the aim of standardizing a limited number of penetration testing methods ehosen among the most commonly used methods in Western Europe and America At the following meeting it was decided to divide the activities inta two parts Dr H Zweck should coordinate the standardization of penetration testing methods in Europe and Prof H Ireland should do the same for the Standard Penetration Test (SPT)

The European group of the Subcommittee met in Wiesbaden in 1963 and discussed a draft for the standardization of the German dynamic sounding test the Dutch static cone penetrometer test and the Swedish weight sounding test These discussions resul ted in the paper Recommended methods for static and dynamic penetration tests (subsurface soundings)

At the Sixth International Conference in Montreal 1965 the secretary of the Subcommittee Prof M Vargas presented one report from the European group and one from the American group Because of the wide divergence of opinions among the members of the Subcommittee it was recommended that the work should be compiled in separate reports and published in the proceectings of the ASCE Geotechnique or other appropriate journals The following reports were therefore published

bull Recommended method for static and dynamic penetration tests (subsurface soundings) 1965 Geotechnique Vol 18 (1968) No l p 98-101

e Ireland HO Moretta O and Vargas M (1970) The dynamic penetration test A standard that is not standardized Geotechnique Vol 20 No 2 p 185-192

At the meeting in Montreal the Subcommittee was dissolved However the European national societies wanted to continue the work on a regional basis and therefore a European Subcommittee was established with Dr H Zweck as chairman There were no reports of the activities of this committe at the international conferences held in Mexico City 1969 and Moscow 1973

In 1974 the Swedish Geotechnical Society organised a European Symposium on Penetration Testing (ESOPT) At this symposium the topic Standardization and future cooperation was discussed The results of these discussions were presented in the ESOPT proceedings Vol 21 p 53-55 It was pointed out that the standardization of penetration equipment and of test proeectures is not only desirable but also necessary and that only a small number of penetrometers should be standardized The suggestion was made that all national geotechnical societies should be encouraged to set up national committees on penetration testing and appoint centact members with the European Subcommittee in order to enlarge the base for the work on standardization

At the ISSMFE Executive Committee meeting in Istanbul in 1975 the Subcommittee was enlarged to nine members

The enlarged Subcommittee had its first meeting in Ghent Belgium in August 1975 Dr F Baguelin France was invited to this meeting as an additional member Mr U Bergdahl Sweden was nominated as secretary of the Subcommittee

At this meeting it was decided to develop proposals for the standardization of the following four tests

Static sounding

Dynamic sounding

Standard Penetration Test

Weight sounding

Four working groups were appointed to perform the writing

The seeond meeting of the enlarged European Subcommittee was held in The Hague Holland in June 1976 At this meeting about 40 delegates from 15 European countries discussed the proposals presented by the four working groups Recommendations for the revision of the proposals were settled with the object of presenting them in a final report to the Executive Committee before the Ninth International Conference in Tokyo 1977

A third meeting of the Subcommittee was held in Stockholm in November 1976 for the final discussion of the report and to give recommendations of the Subcommittee

The European recommended standard for penetration tests was then approved by the Executive Committee at the Tokyo Conference 1977 In addition a recommended standard for light dynamic probing was approved at the Stockholm Conference 1981

2

12 Activities of the International Technical Committee on penetration testing of soils TC 16

A new international ISSMFE Committee on Penetration Testing was appointed for 1982-1985 by the President just after ESOPT II with the Swedish Geotechnical Society as host society and Prof B Broms and Mr U Bergdahl as Chairman and Secretary respectively Invitations were sent to members of ISSMFE in 33 different countries to participate in the work of the Committee

The terms of reference for the Committee were enlarged It was emphazised by the president that the Committee should investigate earrelations and camparisans between different penetration testing methods and the applications and limitations of the methods to prediet the hearing capacity and settlement of shallow footings piers and piles The members of the Committee were also encouraged to earrespond with authors of papers cancerned with penetration testing Early attempts at standardization should be avoided

The Committee met for the first time just after the ESOPT II meeting in Amsterdam and for a seeond time in Helsinki May 1983 in connectionwith the 8th ECSMFE Most of the members were present in Helsinki and it was then settled that the main aim of the Committee should be to work out International Reference Test Proeectures for the following four penetration testing methods

l Cone Penetration Test (CPT) 2 Standard Penetration Test (SPT) 3 Dynamic Probing (DP) 4 Weight Sounding Test (WST)

It was also concluded that it would not be possible for the Committee to perform earrelations and comparisons of the different penetration testing methods before the International Conference in San Francisco in August 1985 but this would be one main topic of an International Symposium on Penetration Testing (ISOPT-1) to be held in 1988

The work of the Committee was organized in four different working parties each cancerned with one of the penetrashytion testing methods mentioned above Each working party prepared a report containing proposals for reference test procedures These reports were then discussed at a Techshynical Committee meeting in San Francisco 1985 The four working parties had the following members

e Standard Penetration Test (SPT)

S Thorburn (UK) Chairman JH Schmertmann (USA) IK Nixon (UK) L Decourt (Brazil) T Muromachi (Japan) E Zolkov (Israel)

bull Cone Penetration Test (CPT)

E De Beer (Belgium) Chairman WJ Heijnen (Netherlands) RG Gampanella (Canada) JC Holden (Australia) M Jamiolkowski (Italy) GA Jones (South Africa) J Schmertmann (USA) G Stefanoff (Bulgaria) J Trofimenkov (USSR)

bull Dynamic Probing (DP)

KJ Melzer (FRG) Chairman G Sanglerat (France) G Stefanoff (Bulgaria) U Bergdahl (Sweden)

bull Weight Sounding Test (WST)

BB Broms (Sweden) Chairman T Muromachi (Japan) U Bergdahl (Sweden)

After the San Fransisco Conference the ISSMFE President renewed the Technical Committee on Penetration Testing with new terms of reference viz

l Propose Reference Test Proeectures for commonly used penetration tests including the piezocone

2 Organise an international conference ISOPT l on penetration testing 20-24 March 1988 in Florida where the proposed Reference Test Proeectures could be discussed as well as the interpretation of the results from different penetration testing methods and to present new developments in penetration testing (eg acoustic devices)

A number of new members were nominated and Mr U Bergdahl and Dr E Sellgren were nominated Chairman and Secretary respectively Mr WJ Heijnen was appointed Co-chairman and Co-secretary

After the committee meeting in San Fransisco the proposals for the Reference Test Proeectures were revised after circulation among all committee members and all ISSMFE member societies Thus also the piezocone was included in the Reference Test Proeecture for Cone Penetration Test The Reference Test Proeectures were discussed at a committee meeting at the 9th ECSMFE in Dublin 1987 and at the ISOPT l in Orlando 1988 A final revision of the proposals has been made after ISOPT l

The first International Symposium on Penetration Testing ISOPT l has been held in Orlando USA 20-24th of March 1988 sponsored by the US National Society of ISSMFE the ASCE Geotechnical Division the ASCE Florida Section and the University of Florida

During this symposium the proposed Reference Test Proeectures were presented as well as papers on interpretation of test results from different penetrometers and earrelations between different test results Also the developments in penetration testing were presented

3

2 RECOMMENDATIONS OF THE ISSMFE TECHNICAL

COMMITIEE ON PENETRATION TESTING OF SOILS

Several attempts have been made since 1957 to internationally standardize different penetration testing methods As mentioned above recommended standards for Europe were approved in 1977 and 1981 However no worldshywide agreement on the equipment and proeectures for penetration testing have been reached Therefore it is a great pleasure for the technical committee now to present such an aggreement and to ask for its approval by ISSMFE

The technical committee has ehosen the term Reference Test Procedure as the term Standard is obligatory in many countries Recommendations are presented as Reference Test Proeecture for four existing penetration testing methods

Cone Penetration Test CPT)

Standard Penetration Test (SPT)

Dynamic Probing (DP)

Weight Sounding Test (WST)

The Reference Test Proeectures presented in Appendices A to D specify not only the main dimensions of the penetrometers and test procedures but also details influencing the test results accurracy in measuring devices etc

Complete reports on the different penetrometers with background use of the penetrometers and evaluation of test results can be find in Proceectings of ISOPT l Orlando 1988

In order to make it easy to find the details for the different penetration testing method the working parties have followed the general organization below

l Scope 2 Definitions 3 Equipment 4 Testing proeecture 5 Precision of messurements 6 Precautions checks and verifications 7 Calibration 8 Special features 9 Reporting of results

10 Deviations from the reference test 11 Explanatory nates and comments

In order to make it possible throughout the world to campare various field test results the Technical Committee also recommends that papers to international conferences and journals should also include test results either performed in accordance with one of the Reference Test Proeectures in Appendices A to D or other methods which can be related to them quantitatively by research It is also recommended that the Reference Test Proeectures should be published separately both in English and French

Considerable progress has been made by the Committees work and this should be used by ISSMFE as a foundation on which to build The committee therefore recommends that the work should continue under a new hast society after the Rio Conference in 1989 if only to serve as a focal point for penetration testing development in the future However in practical terms there are more definitive aspects which a future committee should address This committees suggestions for these which could be adopted

as terms of reference for a future committee are listed below in order of priority as it is realised that the work which could be undertaken during a four year term is limited

(a) Continuing review of reference test proeectures in light of new research findings and new developments (e g piezocone)

(b) Development of reference test proeectures for other tests (eg Marchetti dilatometer pressuremeter) to control new methods early in their development and avoid the problems that have been experienced in the pas t

(c) Critical review of existing earrelations between penetration test results and geotechnical engineering parameters and productian of recommended earrelations applicable to reference tests (This should commence with only a few parameters eg strength rather than tackle all earrelations together)

(d) In the case of the CPT as (c) above but for soil identification in connection with key borings

(e) Investigation of earrelations between different penetration testing methods

f) Review the application of the various methods to the prediction of engineering behaviour (hearing capacity and settlement) and identify the limitations of the various penetration testing methods

The committee has got an invitation from the British Geotechnical Society (BGS) in which BGS express its willingness to serve as hast society for TC 16 during the next four years period Also the societies in France and The Netherlands have expressed similar interest The British Geotechnical Society has proposed Eugene Toolan and Chris Clayton as chairman and Secretary respectively

Respectfully submitted

Mr P Abbona Argentina Mr C Arce Argentina Dr J C Halden Australia Prof E De Beer Belgium Mr E H G Gaelen Belgium Prof A van Wambeke Belgium Dr L Decourt Brazil Mr A H Teixeira Brazil Prof G Stefanoff Bulgaria Dr R G Campanella Canada Ing A Bacmanakova Czechoslovakia Dr H Denver Denmark Dr K J Melzer FRG Prof M Tammirinne Finland Mr S Amar France Prof F Baguelin France Mr L Parez France Prof G Sanglerat France Dr B Kralik Hungary Dr M D Desai India Prof A Komornik Israel Prof J G Zeitlen Israel Prof E Zolkov Israel Prof M Jamiolkowski Italy Dr T Muromachi Japan

4

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

PREFACE

The present report is the final document by the ISSMFE Technical Committee on Penetration Testing of Soils TC 16 which initially was appointed in 1982 and reappoinshyted in 1985 The report contains Reference Test Procedushyres for four different types of penetration testing methods (in English and French)

bull Cone Penetration Test (CPT) e Standard Penetration Test (SPT) bull Dynamic Probing (DP) bull Weight Sounding Test (WST)

According to an agreement between the International Society for Soil Mechanics and Faundatian Engineering the Swedish Geotechnical Society (as host society for TC 16) and the Swedish Geotechncial Institute (SGI) this report is published in SGI Series Information Hopeshyfully this document will be of worldwide use to people cancerned with penetration testing manufacturers conshysultants contractors field engineers researchers and students

Finally I would like to convey my sincere thanks to all the committee members for their deserving work especishyally the Chairmen of the working groups Professor E De Beer Mr S Thorburn and Dr KJ Melzer our Coshychairman Mr WJ Heijnen and our Secretary Dr E Sell shygren

Linkoumlping June 1989

Chairman of the ISSMFE Technical Committee on Penetration Testing of Soils

Ulf Bergdahl Swedish Geotechnical Institute

ISSN 0281-7578

CONTENTS

TABLE DES MATIERES

PREFACE

REPORT OF THE ISSMFE TECHNICAL TESTING OF SOILS - TC 16

COMMITTEE ON PENETRATION 2

APPENDIX A INTERNATIONAL REFERENCE TEST PROCEDURE PENETRATION TEST CPT)

FOR CONE 6

APPENDIX B INTERNATIONAL REFERENCE TEST PROCEDURE PENETRATION TEST (SPT)

FOR THE STANDARD 17

APPENDIX C INTERNATIONAL REFERENCE TEST PROCEDURES PROBING (DP)

FOR DYNAMIC 20

APPENDIX D INTERNATIONAL REFERENCE TEST PROCEDURE SOUNDING TEST (WST)

FOR THE WEIGHT 24

APPENDICE A MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

28

APPENDICE B METHODE DESSAIS DE REFERENCE DE PENETRATION STANDARD SPT)

INTERNATlONALE POUR LESSAI 39

APPENDICE C PROCEDURES INTERNATlONALEs DESSAI PENETROMETRE DYNAMIQUE DP)

DE REFERENCE AU 42

APPENDICE D REFERENCE INTERNATlONALE CONCERNANT LE MODE LESSAI DE PENETRATION PAR CHARGES WST)

OPERATOIRE DE 46

REPORT OF THE ISSMFE TECHNICAL COMMITTEE ON PENETRATION TESTING OF SOILS TC 16

l ACTIVITIES OF THE COMMITTEE ON PENETRATION TESTING

11 Activities of the subcommittee on standardization of penetration testing in Europe

At the Fourth International conference on Soil Mechanics and Faundatian Engineering in London 1957 a Subcommittee on Static and Dynamic Penetration Testing Methods was appointed to study the methods of static and dynamic penetration tests with a view to their standardization

Between the years 1957-1961 the various methods were studied and comparative analyses were carried out However the Subcommittee did not make any recommendations to the Executive Committee at the Fifth International Conference in Paris 1961 It was decided that the work of the Subcommittee should be continued with the aim of standardizing a limited number of penetration testing methods ehosen among the most commonly used methods in Western Europe and America At the following meeting it was decided to divide the activities inta two parts Dr H Zweck should coordinate the standardization of penetration testing methods in Europe and Prof H Ireland should do the same for the Standard Penetration Test (SPT)

The European group of the Subcommittee met in Wiesbaden in 1963 and discussed a draft for the standardization of the German dynamic sounding test the Dutch static cone penetrometer test and the Swedish weight sounding test These discussions resul ted in the paper Recommended methods for static and dynamic penetration tests (subsurface soundings)

At the Sixth International Conference in Montreal 1965 the secretary of the Subcommittee Prof M Vargas presented one report from the European group and one from the American group Because of the wide divergence of opinions among the members of the Subcommittee it was recommended that the work should be compiled in separate reports and published in the proceectings of the ASCE Geotechnique or other appropriate journals The following reports were therefore published

bull Recommended method for static and dynamic penetration tests (subsurface soundings) 1965 Geotechnique Vol 18 (1968) No l p 98-101

e Ireland HO Moretta O and Vargas M (1970) The dynamic penetration test A standard that is not standardized Geotechnique Vol 20 No 2 p 185-192

At the meeting in Montreal the Subcommittee was dissolved However the European national societies wanted to continue the work on a regional basis and therefore a European Subcommittee was established with Dr H Zweck as chairman There were no reports of the activities of this committe at the international conferences held in Mexico City 1969 and Moscow 1973

In 1974 the Swedish Geotechnical Society organised a European Symposium on Penetration Testing (ESOPT) At this symposium the topic Standardization and future cooperation was discussed The results of these discussions were presented in the ESOPT proceedings Vol 21 p 53-55 It was pointed out that the standardization of penetration equipment and of test proeectures is not only desirable but also necessary and that only a small number of penetrometers should be standardized The suggestion was made that all national geotechnical societies should be encouraged to set up national committees on penetration testing and appoint centact members with the European Subcommittee in order to enlarge the base for the work on standardization

At the ISSMFE Executive Committee meeting in Istanbul in 1975 the Subcommittee was enlarged to nine members

The enlarged Subcommittee had its first meeting in Ghent Belgium in August 1975 Dr F Baguelin France was invited to this meeting as an additional member Mr U Bergdahl Sweden was nominated as secretary of the Subcommittee

At this meeting it was decided to develop proposals for the standardization of the following four tests

Static sounding

Dynamic sounding

Standard Penetration Test

Weight sounding

Four working groups were appointed to perform the writing

The seeond meeting of the enlarged European Subcommittee was held in The Hague Holland in June 1976 At this meeting about 40 delegates from 15 European countries discussed the proposals presented by the four working groups Recommendations for the revision of the proposals were settled with the object of presenting them in a final report to the Executive Committee before the Ninth International Conference in Tokyo 1977

A third meeting of the Subcommittee was held in Stockholm in November 1976 for the final discussion of the report and to give recommendations of the Subcommittee

The European recommended standard for penetration tests was then approved by the Executive Committee at the Tokyo Conference 1977 In addition a recommended standard for light dynamic probing was approved at the Stockholm Conference 1981

2

12 Activities of the International Technical Committee on penetration testing of soils TC 16

A new international ISSMFE Committee on Penetration Testing was appointed for 1982-1985 by the President just after ESOPT II with the Swedish Geotechnical Society as host society and Prof B Broms and Mr U Bergdahl as Chairman and Secretary respectively Invitations were sent to members of ISSMFE in 33 different countries to participate in the work of the Committee

The terms of reference for the Committee were enlarged It was emphazised by the president that the Committee should investigate earrelations and camparisans between different penetration testing methods and the applications and limitations of the methods to prediet the hearing capacity and settlement of shallow footings piers and piles The members of the Committee were also encouraged to earrespond with authors of papers cancerned with penetration testing Early attempts at standardization should be avoided

The Committee met for the first time just after the ESOPT II meeting in Amsterdam and for a seeond time in Helsinki May 1983 in connectionwith the 8th ECSMFE Most of the members were present in Helsinki and it was then settled that the main aim of the Committee should be to work out International Reference Test Proeectures for the following four penetration testing methods

l Cone Penetration Test (CPT) 2 Standard Penetration Test (SPT) 3 Dynamic Probing (DP) 4 Weight Sounding Test (WST)

It was also concluded that it would not be possible for the Committee to perform earrelations and comparisons of the different penetration testing methods before the International Conference in San Francisco in August 1985 but this would be one main topic of an International Symposium on Penetration Testing (ISOPT-1) to be held in 1988

The work of the Committee was organized in four different working parties each cancerned with one of the penetrashytion testing methods mentioned above Each working party prepared a report containing proposals for reference test procedures These reports were then discussed at a Techshynical Committee meeting in San Francisco 1985 The four working parties had the following members

e Standard Penetration Test (SPT)

S Thorburn (UK) Chairman JH Schmertmann (USA) IK Nixon (UK) L Decourt (Brazil) T Muromachi (Japan) E Zolkov (Israel)

bull Cone Penetration Test (CPT)

E De Beer (Belgium) Chairman WJ Heijnen (Netherlands) RG Gampanella (Canada) JC Holden (Australia) M Jamiolkowski (Italy) GA Jones (South Africa) J Schmertmann (USA) G Stefanoff (Bulgaria) J Trofimenkov (USSR)

bull Dynamic Probing (DP)

KJ Melzer (FRG) Chairman G Sanglerat (France) G Stefanoff (Bulgaria) U Bergdahl (Sweden)

bull Weight Sounding Test (WST)

BB Broms (Sweden) Chairman T Muromachi (Japan) U Bergdahl (Sweden)

After the San Fransisco Conference the ISSMFE President renewed the Technical Committee on Penetration Testing with new terms of reference viz

l Propose Reference Test Proeectures for commonly used penetration tests including the piezocone

2 Organise an international conference ISOPT l on penetration testing 20-24 March 1988 in Florida where the proposed Reference Test Proeectures could be discussed as well as the interpretation of the results from different penetration testing methods and to present new developments in penetration testing (eg acoustic devices)

A number of new members were nominated and Mr U Bergdahl and Dr E Sellgren were nominated Chairman and Secretary respectively Mr WJ Heijnen was appointed Co-chairman and Co-secretary

After the committee meeting in San Fransisco the proposals for the Reference Test Proeectures were revised after circulation among all committee members and all ISSMFE member societies Thus also the piezocone was included in the Reference Test Proeecture for Cone Penetration Test The Reference Test Proeectures were discussed at a committee meeting at the 9th ECSMFE in Dublin 1987 and at the ISOPT l in Orlando 1988 A final revision of the proposals has been made after ISOPT l

The first International Symposium on Penetration Testing ISOPT l has been held in Orlando USA 20-24th of March 1988 sponsored by the US National Society of ISSMFE the ASCE Geotechnical Division the ASCE Florida Section and the University of Florida

During this symposium the proposed Reference Test Proeectures were presented as well as papers on interpretation of test results from different penetrometers and earrelations between different test results Also the developments in penetration testing were presented

3

2 RECOMMENDATIONS OF THE ISSMFE TECHNICAL

COMMITIEE ON PENETRATION TESTING OF SOILS

Several attempts have been made since 1957 to internationally standardize different penetration testing methods As mentioned above recommended standards for Europe were approved in 1977 and 1981 However no worldshywide agreement on the equipment and proeectures for penetration testing have been reached Therefore it is a great pleasure for the technical committee now to present such an aggreement and to ask for its approval by ISSMFE

The technical committee has ehosen the term Reference Test Procedure as the term Standard is obligatory in many countries Recommendations are presented as Reference Test Proeecture for four existing penetration testing methods

Cone Penetration Test CPT)

Standard Penetration Test (SPT)

Dynamic Probing (DP)

Weight Sounding Test (WST)

The Reference Test Proeectures presented in Appendices A to D specify not only the main dimensions of the penetrometers and test procedures but also details influencing the test results accurracy in measuring devices etc

Complete reports on the different penetrometers with background use of the penetrometers and evaluation of test results can be find in Proceectings of ISOPT l Orlando 1988

In order to make it easy to find the details for the different penetration testing method the working parties have followed the general organization below

l Scope 2 Definitions 3 Equipment 4 Testing proeecture 5 Precision of messurements 6 Precautions checks and verifications 7 Calibration 8 Special features 9 Reporting of results

10 Deviations from the reference test 11 Explanatory nates and comments

In order to make it possible throughout the world to campare various field test results the Technical Committee also recommends that papers to international conferences and journals should also include test results either performed in accordance with one of the Reference Test Proeectures in Appendices A to D or other methods which can be related to them quantitatively by research It is also recommended that the Reference Test Proeectures should be published separately both in English and French

Considerable progress has been made by the Committees work and this should be used by ISSMFE as a foundation on which to build The committee therefore recommends that the work should continue under a new hast society after the Rio Conference in 1989 if only to serve as a focal point for penetration testing development in the future However in practical terms there are more definitive aspects which a future committee should address This committees suggestions for these which could be adopted

as terms of reference for a future committee are listed below in order of priority as it is realised that the work which could be undertaken during a four year term is limited

(a) Continuing review of reference test proeectures in light of new research findings and new developments (e g piezocone)

(b) Development of reference test proeectures for other tests (eg Marchetti dilatometer pressuremeter) to control new methods early in their development and avoid the problems that have been experienced in the pas t

(c) Critical review of existing earrelations between penetration test results and geotechnical engineering parameters and productian of recommended earrelations applicable to reference tests (This should commence with only a few parameters eg strength rather than tackle all earrelations together)

(d) In the case of the CPT as (c) above but for soil identification in connection with key borings

(e) Investigation of earrelations between different penetration testing methods

f) Review the application of the various methods to the prediction of engineering behaviour (hearing capacity and settlement) and identify the limitations of the various penetration testing methods

The committee has got an invitation from the British Geotechnical Society (BGS) in which BGS express its willingness to serve as hast society for TC 16 during the next four years period Also the societies in France and The Netherlands have expressed similar interest The British Geotechnical Society has proposed Eugene Toolan and Chris Clayton as chairman and Secretary respectively

Respectfully submitted

Mr P Abbona Argentina Mr C Arce Argentina Dr J C Halden Australia Prof E De Beer Belgium Mr E H G Gaelen Belgium Prof A van Wambeke Belgium Dr L Decourt Brazil Mr A H Teixeira Brazil Prof G Stefanoff Bulgaria Dr R G Campanella Canada Ing A Bacmanakova Czechoslovakia Dr H Denver Denmark Dr K J Melzer FRG Prof M Tammirinne Finland Mr S Amar France Prof F Baguelin France Mr L Parez France Prof G Sanglerat France Dr B Kralik Hungary Dr M D Desai India Prof A Komornik Israel Prof J G Zeitlen Israel Prof E Zolkov Israel Prof M Jamiolkowski Italy Dr T Muromachi Japan

4

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

CONTENTS

TABLE DES MATIERES

PREFACE

REPORT OF THE ISSMFE TECHNICAL TESTING OF SOILS - TC 16

COMMITTEE ON PENETRATION 2

APPENDIX A INTERNATIONAL REFERENCE TEST PROCEDURE PENETRATION TEST CPT)

FOR CONE 6

APPENDIX B INTERNATIONAL REFERENCE TEST PROCEDURE PENETRATION TEST (SPT)

FOR THE STANDARD 17

APPENDIX C INTERNATIONAL REFERENCE TEST PROCEDURES PROBING (DP)

FOR DYNAMIC 20

APPENDIX D INTERNATIONAL REFERENCE TEST PROCEDURE SOUNDING TEST (WST)

FOR THE WEIGHT 24

APPENDICE A MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

28

APPENDICE B METHODE DESSAIS DE REFERENCE DE PENETRATION STANDARD SPT)

INTERNATlONALE POUR LESSAI 39

APPENDICE C PROCEDURES INTERNATlONALEs DESSAI PENETROMETRE DYNAMIQUE DP)

DE REFERENCE AU 42

APPENDICE D REFERENCE INTERNATlONALE CONCERNANT LE MODE LESSAI DE PENETRATION PAR CHARGES WST)

OPERATOIRE DE 46

REPORT OF THE ISSMFE TECHNICAL COMMITTEE ON PENETRATION TESTING OF SOILS TC 16

l ACTIVITIES OF THE COMMITTEE ON PENETRATION TESTING

11 Activities of the subcommittee on standardization of penetration testing in Europe

At the Fourth International conference on Soil Mechanics and Faundatian Engineering in London 1957 a Subcommittee on Static and Dynamic Penetration Testing Methods was appointed to study the methods of static and dynamic penetration tests with a view to their standardization

Between the years 1957-1961 the various methods were studied and comparative analyses were carried out However the Subcommittee did not make any recommendations to the Executive Committee at the Fifth International Conference in Paris 1961 It was decided that the work of the Subcommittee should be continued with the aim of standardizing a limited number of penetration testing methods ehosen among the most commonly used methods in Western Europe and America At the following meeting it was decided to divide the activities inta two parts Dr H Zweck should coordinate the standardization of penetration testing methods in Europe and Prof H Ireland should do the same for the Standard Penetration Test (SPT)

The European group of the Subcommittee met in Wiesbaden in 1963 and discussed a draft for the standardization of the German dynamic sounding test the Dutch static cone penetrometer test and the Swedish weight sounding test These discussions resul ted in the paper Recommended methods for static and dynamic penetration tests (subsurface soundings)

At the Sixth International Conference in Montreal 1965 the secretary of the Subcommittee Prof M Vargas presented one report from the European group and one from the American group Because of the wide divergence of opinions among the members of the Subcommittee it was recommended that the work should be compiled in separate reports and published in the proceectings of the ASCE Geotechnique or other appropriate journals The following reports were therefore published

bull Recommended method for static and dynamic penetration tests (subsurface soundings) 1965 Geotechnique Vol 18 (1968) No l p 98-101

e Ireland HO Moretta O and Vargas M (1970) The dynamic penetration test A standard that is not standardized Geotechnique Vol 20 No 2 p 185-192

At the meeting in Montreal the Subcommittee was dissolved However the European national societies wanted to continue the work on a regional basis and therefore a European Subcommittee was established with Dr H Zweck as chairman There were no reports of the activities of this committe at the international conferences held in Mexico City 1969 and Moscow 1973

In 1974 the Swedish Geotechnical Society organised a European Symposium on Penetration Testing (ESOPT) At this symposium the topic Standardization and future cooperation was discussed The results of these discussions were presented in the ESOPT proceedings Vol 21 p 53-55 It was pointed out that the standardization of penetration equipment and of test proeectures is not only desirable but also necessary and that only a small number of penetrometers should be standardized The suggestion was made that all national geotechnical societies should be encouraged to set up national committees on penetration testing and appoint centact members with the European Subcommittee in order to enlarge the base for the work on standardization

At the ISSMFE Executive Committee meeting in Istanbul in 1975 the Subcommittee was enlarged to nine members

The enlarged Subcommittee had its first meeting in Ghent Belgium in August 1975 Dr F Baguelin France was invited to this meeting as an additional member Mr U Bergdahl Sweden was nominated as secretary of the Subcommittee

At this meeting it was decided to develop proposals for the standardization of the following four tests

Static sounding

Dynamic sounding

Standard Penetration Test

Weight sounding

Four working groups were appointed to perform the writing

The seeond meeting of the enlarged European Subcommittee was held in The Hague Holland in June 1976 At this meeting about 40 delegates from 15 European countries discussed the proposals presented by the four working groups Recommendations for the revision of the proposals were settled with the object of presenting them in a final report to the Executive Committee before the Ninth International Conference in Tokyo 1977

A third meeting of the Subcommittee was held in Stockholm in November 1976 for the final discussion of the report and to give recommendations of the Subcommittee

The European recommended standard for penetration tests was then approved by the Executive Committee at the Tokyo Conference 1977 In addition a recommended standard for light dynamic probing was approved at the Stockholm Conference 1981

2

12 Activities of the International Technical Committee on penetration testing of soils TC 16

A new international ISSMFE Committee on Penetration Testing was appointed for 1982-1985 by the President just after ESOPT II with the Swedish Geotechnical Society as host society and Prof B Broms and Mr U Bergdahl as Chairman and Secretary respectively Invitations were sent to members of ISSMFE in 33 different countries to participate in the work of the Committee

The terms of reference for the Committee were enlarged It was emphazised by the president that the Committee should investigate earrelations and camparisans between different penetration testing methods and the applications and limitations of the methods to prediet the hearing capacity and settlement of shallow footings piers and piles The members of the Committee were also encouraged to earrespond with authors of papers cancerned with penetration testing Early attempts at standardization should be avoided

The Committee met for the first time just after the ESOPT II meeting in Amsterdam and for a seeond time in Helsinki May 1983 in connectionwith the 8th ECSMFE Most of the members were present in Helsinki and it was then settled that the main aim of the Committee should be to work out International Reference Test Proeectures for the following four penetration testing methods

l Cone Penetration Test (CPT) 2 Standard Penetration Test (SPT) 3 Dynamic Probing (DP) 4 Weight Sounding Test (WST)

It was also concluded that it would not be possible for the Committee to perform earrelations and comparisons of the different penetration testing methods before the International Conference in San Francisco in August 1985 but this would be one main topic of an International Symposium on Penetration Testing (ISOPT-1) to be held in 1988

The work of the Committee was organized in four different working parties each cancerned with one of the penetrashytion testing methods mentioned above Each working party prepared a report containing proposals for reference test procedures These reports were then discussed at a Techshynical Committee meeting in San Francisco 1985 The four working parties had the following members

e Standard Penetration Test (SPT)

S Thorburn (UK) Chairman JH Schmertmann (USA) IK Nixon (UK) L Decourt (Brazil) T Muromachi (Japan) E Zolkov (Israel)

bull Cone Penetration Test (CPT)

E De Beer (Belgium) Chairman WJ Heijnen (Netherlands) RG Gampanella (Canada) JC Holden (Australia) M Jamiolkowski (Italy) GA Jones (South Africa) J Schmertmann (USA) G Stefanoff (Bulgaria) J Trofimenkov (USSR)

bull Dynamic Probing (DP)

KJ Melzer (FRG) Chairman G Sanglerat (France) G Stefanoff (Bulgaria) U Bergdahl (Sweden)

bull Weight Sounding Test (WST)

BB Broms (Sweden) Chairman T Muromachi (Japan) U Bergdahl (Sweden)

After the San Fransisco Conference the ISSMFE President renewed the Technical Committee on Penetration Testing with new terms of reference viz

l Propose Reference Test Proeectures for commonly used penetration tests including the piezocone

2 Organise an international conference ISOPT l on penetration testing 20-24 March 1988 in Florida where the proposed Reference Test Proeectures could be discussed as well as the interpretation of the results from different penetration testing methods and to present new developments in penetration testing (eg acoustic devices)

A number of new members were nominated and Mr U Bergdahl and Dr E Sellgren were nominated Chairman and Secretary respectively Mr WJ Heijnen was appointed Co-chairman and Co-secretary

After the committee meeting in San Fransisco the proposals for the Reference Test Proeectures were revised after circulation among all committee members and all ISSMFE member societies Thus also the piezocone was included in the Reference Test Proeecture for Cone Penetration Test The Reference Test Proeectures were discussed at a committee meeting at the 9th ECSMFE in Dublin 1987 and at the ISOPT l in Orlando 1988 A final revision of the proposals has been made after ISOPT l

The first International Symposium on Penetration Testing ISOPT l has been held in Orlando USA 20-24th of March 1988 sponsored by the US National Society of ISSMFE the ASCE Geotechnical Division the ASCE Florida Section and the University of Florida

During this symposium the proposed Reference Test Proeectures were presented as well as papers on interpretation of test results from different penetrometers and earrelations between different test results Also the developments in penetration testing were presented

3

2 RECOMMENDATIONS OF THE ISSMFE TECHNICAL

COMMITIEE ON PENETRATION TESTING OF SOILS

Several attempts have been made since 1957 to internationally standardize different penetration testing methods As mentioned above recommended standards for Europe were approved in 1977 and 1981 However no worldshywide agreement on the equipment and proeectures for penetration testing have been reached Therefore it is a great pleasure for the technical committee now to present such an aggreement and to ask for its approval by ISSMFE

The technical committee has ehosen the term Reference Test Procedure as the term Standard is obligatory in many countries Recommendations are presented as Reference Test Proeecture for four existing penetration testing methods

Cone Penetration Test CPT)

Standard Penetration Test (SPT)

Dynamic Probing (DP)

Weight Sounding Test (WST)

The Reference Test Proeectures presented in Appendices A to D specify not only the main dimensions of the penetrometers and test procedures but also details influencing the test results accurracy in measuring devices etc

Complete reports on the different penetrometers with background use of the penetrometers and evaluation of test results can be find in Proceectings of ISOPT l Orlando 1988

In order to make it easy to find the details for the different penetration testing method the working parties have followed the general organization below

l Scope 2 Definitions 3 Equipment 4 Testing proeecture 5 Precision of messurements 6 Precautions checks and verifications 7 Calibration 8 Special features 9 Reporting of results

10 Deviations from the reference test 11 Explanatory nates and comments

In order to make it possible throughout the world to campare various field test results the Technical Committee also recommends that papers to international conferences and journals should also include test results either performed in accordance with one of the Reference Test Proeectures in Appendices A to D or other methods which can be related to them quantitatively by research It is also recommended that the Reference Test Proeectures should be published separately both in English and French

Considerable progress has been made by the Committees work and this should be used by ISSMFE as a foundation on which to build The committee therefore recommends that the work should continue under a new hast society after the Rio Conference in 1989 if only to serve as a focal point for penetration testing development in the future However in practical terms there are more definitive aspects which a future committee should address This committees suggestions for these which could be adopted

as terms of reference for a future committee are listed below in order of priority as it is realised that the work which could be undertaken during a four year term is limited

(a) Continuing review of reference test proeectures in light of new research findings and new developments (e g piezocone)

(b) Development of reference test proeectures for other tests (eg Marchetti dilatometer pressuremeter) to control new methods early in their development and avoid the problems that have been experienced in the pas t

(c) Critical review of existing earrelations between penetration test results and geotechnical engineering parameters and productian of recommended earrelations applicable to reference tests (This should commence with only a few parameters eg strength rather than tackle all earrelations together)

(d) In the case of the CPT as (c) above but for soil identification in connection with key borings

(e) Investigation of earrelations between different penetration testing methods

f) Review the application of the various methods to the prediction of engineering behaviour (hearing capacity and settlement) and identify the limitations of the various penetration testing methods

The committee has got an invitation from the British Geotechnical Society (BGS) in which BGS express its willingness to serve as hast society for TC 16 during the next four years period Also the societies in France and The Netherlands have expressed similar interest The British Geotechnical Society has proposed Eugene Toolan and Chris Clayton as chairman and Secretary respectively

Respectfully submitted

Mr P Abbona Argentina Mr C Arce Argentina Dr J C Halden Australia Prof E De Beer Belgium Mr E H G Gaelen Belgium Prof A van Wambeke Belgium Dr L Decourt Brazil Mr A H Teixeira Brazil Prof G Stefanoff Bulgaria Dr R G Campanella Canada Ing A Bacmanakova Czechoslovakia Dr H Denver Denmark Dr K J Melzer FRG Prof M Tammirinne Finland Mr S Amar France Prof F Baguelin France Mr L Parez France Prof G Sanglerat France Dr B Kralik Hungary Dr M D Desai India Prof A Komornik Israel Prof J G Zeitlen Israel Prof E Zolkov Israel Prof M Jamiolkowski Italy Dr T Muromachi Japan

4

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

REPORT OF THE ISSMFE TECHNICAL COMMITTEE ON PENETRATION TESTING OF SOILS TC 16

l ACTIVITIES OF THE COMMITTEE ON PENETRATION TESTING

11 Activities of the subcommittee on standardization of penetration testing in Europe

At the Fourth International conference on Soil Mechanics and Faundatian Engineering in London 1957 a Subcommittee on Static and Dynamic Penetration Testing Methods was appointed to study the methods of static and dynamic penetration tests with a view to their standardization

Between the years 1957-1961 the various methods were studied and comparative analyses were carried out However the Subcommittee did not make any recommendations to the Executive Committee at the Fifth International Conference in Paris 1961 It was decided that the work of the Subcommittee should be continued with the aim of standardizing a limited number of penetration testing methods ehosen among the most commonly used methods in Western Europe and America At the following meeting it was decided to divide the activities inta two parts Dr H Zweck should coordinate the standardization of penetration testing methods in Europe and Prof H Ireland should do the same for the Standard Penetration Test (SPT)

The European group of the Subcommittee met in Wiesbaden in 1963 and discussed a draft for the standardization of the German dynamic sounding test the Dutch static cone penetrometer test and the Swedish weight sounding test These discussions resul ted in the paper Recommended methods for static and dynamic penetration tests (subsurface soundings)

At the Sixth International Conference in Montreal 1965 the secretary of the Subcommittee Prof M Vargas presented one report from the European group and one from the American group Because of the wide divergence of opinions among the members of the Subcommittee it was recommended that the work should be compiled in separate reports and published in the proceectings of the ASCE Geotechnique or other appropriate journals The following reports were therefore published

bull Recommended method for static and dynamic penetration tests (subsurface soundings) 1965 Geotechnique Vol 18 (1968) No l p 98-101

e Ireland HO Moretta O and Vargas M (1970) The dynamic penetration test A standard that is not standardized Geotechnique Vol 20 No 2 p 185-192

At the meeting in Montreal the Subcommittee was dissolved However the European national societies wanted to continue the work on a regional basis and therefore a European Subcommittee was established with Dr H Zweck as chairman There were no reports of the activities of this committe at the international conferences held in Mexico City 1969 and Moscow 1973

In 1974 the Swedish Geotechnical Society organised a European Symposium on Penetration Testing (ESOPT) At this symposium the topic Standardization and future cooperation was discussed The results of these discussions were presented in the ESOPT proceedings Vol 21 p 53-55 It was pointed out that the standardization of penetration equipment and of test proeectures is not only desirable but also necessary and that only a small number of penetrometers should be standardized The suggestion was made that all national geotechnical societies should be encouraged to set up national committees on penetration testing and appoint centact members with the European Subcommittee in order to enlarge the base for the work on standardization

At the ISSMFE Executive Committee meeting in Istanbul in 1975 the Subcommittee was enlarged to nine members

The enlarged Subcommittee had its first meeting in Ghent Belgium in August 1975 Dr F Baguelin France was invited to this meeting as an additional member Mr U Bergdahl Sweden was nominated as secretary of the Subcommittee

At this meeting it was decided to develop proposals for the standardization of the following four tests

Static sounding

Dynamic sounding

Standard Penetration Test

Weight sounding

Four working groups were appointed to perform the writing

The seeond meeting of the enlarged European Subcommittee was held in The Hague Holland in June 1976 At this meeting about 40 delegates from 15 European countries discussed the proposals presented by the four working groups Recommendations for the revision of the proposals were settled with the object of presenting them in a final report to the Executive Committee before the Ninth International Conference in Tokyo 1977

A third meeting of the Subcommittee was held in Stockholm in November 1976 for the final discussion of the report and to give recommendations of the Subcommittee

The European recommended standard for penetration tests was then approved by the Executive Committee at the Tokyo Conference 1977 In addition a recommended standard for light dynamic probing was approved at the Stockholm Conference 1981

2

12 Activities of the International Technical Committee on penetration testing of soils TC 16

A new international ISSMFE Committee on Penetration Testing was appointed for 1982-1985 by the President just after ESOPT II with the Swedish Geotechnical Society as host society and Prof B Broms and Mr U Bergdahl as Chairman and Secretary respectively Invitations were sent to members of ISSMFE in 33 different countries to participate in the work of the Committee

The terms of reference for the Committee were enlarged It was emphazised by the president that the Committee should investigate earrelations and camparisans between different penetration testing methods and the applications and limitations of the methods to prediet the hearing capacity and settlement of shallow footings piers and piles The members of the Committee were also encouraged to earrespond with authors of papers cancerned with penetration testing Early attempts at standardization should be avoided

The Committee met for the first time just after the ESOPT II meeting in Amsterdam and for a seeond time in Helsinki May 1983 in connectionwith the 8th ECSMFE Most of the members were present in Helsinki and it was then settled that the main aim of the Committee should be to work out International Reference Test Proeectures for the following four penetration testing methods

l Cone Penetration Test (CPT) 2 Standard Penetration Test (SPT) 3 Dynamic Probing (DP) 4 Weight Sounding Test (WST)

It was also concluded that it would not be possible for the Committee to perform earrelations and comparisons of the different penetration testing methods before the International Conference in San Francisco in August 1985 but this would be one main topic of an International Symposium on Penetration Testing (ISOPT-1) to be held in 1988

The work of the Committee was organized in four different working parties each cancerned with one of the penetrashytion testing methods mentioned above Each working party prepared a report containing proposals for reference test procedures These reports were then discussed at a Techshynical Committee meeting in San Francisco 1985 The four working parties had the following members

e Standard Penetration Test (SPT)

S Thorburn (UK) Chairman JH Schmertmann (USA) IK Nixon (UK) L Decourt (Brazil) T Muromachi (Japan) E Zolkov (Israel)

bull Cone Penetration Test (CPT)

E De Beer (Belgium) Chairman WJ Heijnen (Netherlands) RG Gampanella (Canada) JC Holden (Australia) M Jamiolkowski (Italy) GA Jones (South Africa) J Schmertmann (USA) G Stefanoff (Bulgaria) J Trofimenkov (USSR)

bull Dynamic Probing (DP)

KJ Melzer (FRG) Chairman G Sanglerat (France) G Stefanoff (Bulgaria) U Bergdahl (Sweden)

bull Weight Sounding Test (WST)

BB Broms (Sweden) Chairman T Muromachi (Japan) U Bergdahl (Sweden)

After the San Fransisco Conference the ISSMFE President renewed the Technical Committee on Penetration Testing with new terms of reference viz

l Propose Reference Test Proeectures for commonly used penetration tests including the piezocone

2 Organise an international conference ISOPT l on penetration testing 20-24 March 1988 in Florida where the proposed Reference Test Proeectures could be discussed as well as the interpretation of the results from different penetration testing methods and to present new developments in penetration testing (eg acoustic devices)

A number of new members were nominated and Mr U Bergdahl and Dr E Sellgren were nominated Chairman and Secretary respectively Mr WJ Heijnen was appointed Co-chairman and Co-secretary

After the committee meeting in San Fransisco the proposals for the Reference Test Proeectures were revised after circulation among all committee members and all ISSMFE member societies Thus also the piezocone was included in the Reference Test Proeecture for Cone Penetration Test The Reference Test Proeectures were discussed at a committee meeting at the 9th ECSMFE in Dublin 1987 and at the ISOPT l in Orlando 1988 A final revision of the proposals has been made after ISOPT l

The first International Symposium on Penetration Testing ISOPT l has been held in Orlando USA 20-24th of March 1988 sponsored by the US National Society of ISSMFE the ASCE Geotechnical Division the ASCE Florida Section and the University of Florida

During this symposium the proposed Reference Test Proeectures were presented as well as papers on interpretation of test results from different penetrometers and earrelations between different test results Also the developments in penetration testing were presented

3

2 RECOMMENDATIONS OF THE ISSMFE TECHNICAL

COMMITIEE ON PENETRATION TESTING OF SOILS

Several attempts have been made since 1957 to internationally standardize different penetration testing methods As mentioned above recommended standards for Europe were approved in 1977 and 1981 However no worldshywide agreement on the equipment and proeectures for penetration testing have been reached Therefore it is a great pleasure for the technical committee now to present such an aggreement and to ask for its approval by ISSMFE

The technical committee has ehosen the term Reference Test Procedure as the term Standard is obligatory in many countries Recommendations are presented as Reference Test Proeecture for four existing penetration testing methods

Cone Penetration Test CPT)

Standard Penetration Test (SPT)

Dynamic Probing (DP)

Weight Sounding Test (WST)

The Reference Test Proeectures presented in Appendices A to D specify not only the main dimensions of the penetrometers and test procedures but also details influencing the test results accurracy in measuring devices etc

Complete reports on the different penetrometers with background use of the penetrometers and evaluation of test results can be find in Proceectings of ISOPT l Orlando 1988

In order to make it easy to find the details for the different penetration testing method the working parties have followed the general organization below

l Scope 2 Definitions 3 Equipment 4 Testing proeecture 5 Precision of messurements 6 Precautions checks and verifications 7 Calibration 8 Special features 9 Reporting of results

10 Deviations from the reference test 11 Explanatory nates and comments

In order to make it possible throughout the world to campare various field test results the Technical Committee also recommends that papers to international conferences and journals should also include test results either performed in accordance with one of the Reference Test Proeectures in Appendices A to D or other methods which can be related to them quantitatively by research It is also recommended that the Reference Test Proeectures should be published separately both in English and French

Considerable progress has been made by the Committees work and this should be used by ISSMFE as a foundation on which to build The committee therefore recommends that the work should continue under a new hast society after the Rio Conference in 1989 if only to serve as a focal point for penetration testing development in the future However in practical terms there are more definitive aspects which a future committee should address This committees suggestions for these which could be adopted

as terms of reference for a future committee are listed below in order of priority as it is realised that the work which could be undertaken during a four year term is limited

(a) Continuing review of reference test proeectures in light of new research findings and new developments (e g piezocone)

(b) Development of reference test proeectures for other tests (eg Marchetti dilatometer pressuremeter) to control new methods early in their development and avoid the problems that have been experienced in the pas t

(c) Critical review of existing earrelations between penetration test results and geotechnical engineering parameters and productian of recommended earrelations applicable to reference tests (This should commence with only a few parameters eg strength rather than tackle all earrelations together)

(d) In the case of the CPT as (c) above but for soil identification in connection with key borings

(e) Investigation of earrelations between different penetration testing methods

f) Review the application of the various methods to the prediction of engineering behaviour (hearing capacity and settlement) and identify the limitations of the various penetration testing methods

The committee has got an invitation from the British Geotechnical Society (BGS) in which BGS express its willingness to serve as hast society for TC 16 during the next four years period Also the societies in France and The Netherlands have expressed similar interest The British Geotechnical Society has proposed Eugene Toolan and Chris Clayton as chairman and Secretary respectively

Respectfully submitted

Mr P Abbona Argentina Mr C Arce Argentina Dr J C Halden Australia Prof E De Beer Belgium Mr E H G Gaelen Belgium Prof A van Wambeke Belgium Dr L Decourt Brazil Mr A H Teixeira Brazil Prof G Stefanoff Bulgaria Dr R G Campanella Canada Ing A Bacmanakova Czechoslovakia Dr H Denver Denmark Dr K J Melzer FRG Prof M Tammirinne Finland Mr S Amar France Prof F Baguelin France Mr L Parez France Prof G Sanglerat France Dr B Kralik Hungary Dr M D Desai India Prof A Komornik Israel Prof J G Zeitlen Israel Prof E Zolkov Israel Prof M Jamiolkowski Italy Dr T Muromachi Japan

4

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

12 Activities of the International Technical Committee on penetration testing of soils TC 16

A new international ISSMFE Committee on Penetration Testing was appointed for 1982-1985 by the President just after ESOPT II with the Swedish Geotechnical Society as host society and Prof B Broms and Mr U Bergdahl as Chairman and Secretary respectively Invitations were sent to members of ISSMFE in 33 different countries to participate in the work of the Committee

The terms of reference for the Committee were enlarged It was emphazised by the president that the Committee should investigate earrelations and camparisans between different penetration testing methods and the applications and limitations of the methods to prediet the hearing capacity and settlement of shallow footings piers and piles The members of the Committee were also encouraged to earrespond with authors of papers cancerned with penetration testing Early attempts at standardization should be avoided

The Committee met for the first time just after the ESOPT II meeting in Amsterdam and for a seeond time in Helsinki May 1983 in connectionwith the 8th ECSMFE Most of the members were present in Helsinki and it was then settled that the main aim of the Committee should be to work out International Reference Test Proeectures for the following four penetration testing methods

l Cone Penetration Test (CPT) 2 Standard Penetration Test (SPT) 3 Dynamic Probing (DP) 4 Weight Sounding Test (WST)

It was also concluded that it would not be possible for the Committee to perform earrelations and comparisons of the different penetration testing methods before the International Conference in San Francisco in August 1985 but this would be one main topic of an International Symposium on Penetration Testing (ISOPT-1) to be held in 1988

The work of the Committee was organized in four different working parties each cancerned with one of the penetrashytion testing methods mentioned above Each working party prepared a report containing proposals for reference test procedures These reports were then discussed at a Techshynical Committee meeting in San Francisco 1985 The four working parties had the following members

e Standard Penetration Test (SPT)

S Thorburn (UK) Chairman JH Schmertmann (USA) IK Nixon (UK) L Decourt (Brazil) T Muromachi (Japan) E Zolkov (Israel)

bull Cone Penetration Test (CPT)

E De Beer (Belgium) Chairman WJ Heijnen (Netherlands) RG Gampanella (Canada) JC Holden (Australia) M Jamiolkowski (Italy) GA Jones (South Africa) J Schmertmann (USA) G Stefanoff (Bulgaria) J Trofimenkov (USSR)

bull Dynamic Probing (DP)

KJ Melzer (FRG) Chairman G Sanglerat (France) G Stefanoff (Bulgaria) U Bergdahl (Sweden)

bull Weight Sounding Test (WST)

BB Broms (Sweden) Chairman T Muromachi (Japan) U Bergdahl (Sweden)

After the San Fransisco Conference the ISSMFE President renewed the Technical Committee on Penetration Testing with new terms of reference viz

l Propose Reference Test Proeectures for commonly used penetration tests including the piezocone

2 Organise an international conference ISOPT l on penetration testing 20-24 March 1988 in Florida where the proposed Reference Test Proeectures could be discussed as well as the interpretation of the results from different penetration testing methods and to present new developments in penetration testing (eg acoustic devices)

A number of new members were nominated and Mr U Bergdahl and Dr E Sellgren were nominated Chairman and Secretary respectively Mr WJ Heijnen was appointed Co-chairman and Co-secretary

After the committee meeting in San Fransisco the proposals for the Reference Test Proeectures were revised after circulation among all committee members and all ISSMFE member societies Thus also the piezocone was included in the Reference Test Proeecture for Cone Penetration Test The Reference Test Proeectures were discussed at a committee meeting at the 9th ECSMFE in Dublin 1987 and at the ISOPT l in Orlando 1988 A final revision of the proposals has been made after ISOPT l

The first International Symposium on Penetration Testing ISOPT l has been held in Orlando USA 20-24th of March 1988 sponsored by the US National Society of ISSMFE the ASCE Geotechnical Division the ASCE Florida Section and the University of Florida

During this symposium the proposed Reference Test Proeectures were presented as well as papers on interpretation of test results from different penetrometers and earrelations between different test results Also the developments in penetration testing were presented

3

2 RECOMMENDATIONS OF THE ISSMFE TECHNICAL

COMMITIEE ON PENETRATION TESTING OF SOILS

Several attempts have been made since 1957 to internationally standardize different penetration testing methods As mentioned above recommended standards for Europe were approved in 1977 and 1981 However no worldshywide agreement on the equipment and proeectures for penetration testing have been reached Therefore it is a great pleasure for the technical committee now to present such an aggreement and to ask for its approval by ISSMFE

The technical committee has ehosen the term Reference Test Procedure as the term Standard is obligatory in many countries Recommendations are presented as Reference Test Proeecture for four existing penetration testing methods

Cone Penetration Test CPT)

Standard Penetration Test (SPT)

Dynamic Probing (DP)

Weight Sounding Test (WST)

The Reference Test Proeectures presented in Appendices A to D specify not only the main dimensions of the penetrometers and test procedures but also details influencing the test results accurracy in measuring devices etc

Complete reports on the different penetrometers with background use of the penetrometers and evaluation of test results can be find in Proceectings of ISOPT l Orlando 1988

In order to make it easy to find the details for the different penetration testing method the working parties have followed the general organization below

l Scope 2 Definitions 3 Equipment 4 Testing proeecture 5 Precision of messurements 6 Precautions checks and verifications 7 Calibration 8 Special features 9 Reporting of results

10 Deviations from the reference test 11 Explanatory nates and comments

In order to make it possible throughout the world to campare various field test results the Technical Committee also recommends that papers to international conferences and journals should also include test results either performed in accordance with one of the Reference Test Proeectures in Appendices A to D or other methods which can be related to them quantitatively by research It is also recommended that the Reference Test Proeectures should be published separately both in English and French

Considerable progress has been made by the Committees work and this should be used by ISSMFE as a foundation on which to build The committee therefore recommends that the work should continue under a new hast society after the Rio Conference in 1989 if only to serve as a focal point for penetration testing development in the future However in practical terms there are more definitive aspects which a future committee should address This committees suggestions for these which could be adopted

as terms of reference for a future committee are listed below in order of priority as it is realised that the work which could be undertaken during a four year term is limited

(a) Continuing review of reference test proeectures in light of new research findings and new developments (e g piezocone)

(b) Development of reference test proeectures for other tests (eg Marchetti dilatometer pressuremeter) to control new methods early in their development and avoid the problems that have been experienced in the pas t

(c) Critical review of existing earrelations between penetration test results and geotechnical engineering parameters and productian of recommended earrelations applicable to reference tests (This should commence with only a few parameters eg strength rather than tackle all earrelations together)

(d) In the case of the CPT as (c) above but for soil identification in connection with key borings

(e) Investigation of earrelations between different penetration testing methods

f) Review the application of the various methods to the prediction of engineering behaviour (hearing capacity and settlement) and identify the limitations of the various penetration testing methods

The committee has got an invitation from the British Geotechnical Society (BGS) in which BGS express its willingness to serve as hast society for TC 16 during the next four years period Also the societies in France and The Netherlands have expressed similar interest The British Geotechnical Society has proposed Eugene Toolan and Chris Clayton as chairman and Secretary respectively

Respectfully submitted

Mr P Abbona Argentina Mr C Arce Argentina Dr J C Halden Australia Prof E De Beer Belgium Mr E H G Gaelen Belgium Prof A van Wambeke Belgium Dr L Decourt Brazil Mr A H Teixeira Brazil Prof G Stefanoff Bulgaria Dr R G Campanella Canada Ing A Bacmanakova Czechoslovakia Dr H Denver Denmark Dr K J Melzer FRG Prof M Tammirinne Finland Mr S Amar France Prof F Baguelin France Mr L Parez France Prof G Sanglerat France Dr B Kralik Hungary Dr M D Desai India Prof A Komornik Israel Prof J G Zeitlen Israel Prof E Zolkov Israel Prof M Jamiolkowski Italy Dr T Muromachi Japan

4

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

2 RECOMMENDATIONS OF THE ISSMFE TECHNICAL

COMMITIEE ON PENETRATION TESTING OF SOILS

Several attempts have been made since 1957 to internationally standardize different penetration testing methods As mentioned above recommended standards for Europe were approved in 1977 and 1981 However no worldshywide agreement on the equipment and proeectures for penetration testing have been reached Therefore it is a great pleasure for the technical committee now to present such an aggreement and to ask for its approval by ISSMFE

The technical committee has ehosen the term Reference Test Procedure as the term Standard is obligatory in many countries Recommendations are presented as Reference Test Proeecture for four existing penetration testing methods

Cone Penetration Test CPT)

Standard Penetration Test (SPT)

Dynamic Probing (DP)

Weight Sounding Test (WST)

The Reference Test Proeectures presented in Appendices A to D specify not only the main dimensions of the penetrometers and test procedures but also details influencing the test results accurracy in measuring devices etc

Complete reports on the different penetrometers with background use of the penetrometers and evaluation of test results can be find in Proceectings of ISOPT l Orlando 1988

In order to make it easy to find the details for the different penetration testing method the working parties have followed the general organization below

l Scope 2 Definitions 3 Equipment 4 Testing proeecture 5 Precision of messurements 6 Precautions checks and verifications 7 Calibration 8 Special features 9 Reporting of results

10 Deviations from the reference test 11 Explanatory nates and comments

In order to make it possible throughout the world to campare various field test results the Technical Committee also recommends that papers to international conferences and journals should also include test results either performed in accordance with one of the Reference Test Proeectures in Appendices A to D or other methods which can be related to them quantitatively by research It is also recommended that the Reference Test Proeectures should be published separately both in English and French

Considerable progress has been made by the Committees work and this should be used by ISSMFE as a foundation on which to build The committee therefore recommends that the work should continue under a new hast society after the Rio Conference in 1989 if only to serve as a focal point for penetration testing development in the future However in practical terms there are more definitive aspects which a future committee should address This committees suggestions for these which could be adopted

as terms of reference for a future committee are listed below in order of priority as it is realised that the work which could be undertaken during a four year term is limited

(a) Continuing review of reference test proeectures in light of new research findings and new developments (e g piezocone)

(b) Development of reference test proeectures for other tests (eg Marchetti dilatometer pressuremeter) to control new methods early in their development and avoid the problems that have been experienced in the pas t

(c) Critical review of existing earrelations between penetration test results and geotechnical engineering parameters and productian of recommended earrelations applicable to reference tests (This should commence with only a few parameters eg strength rather than tackle all earrelations together)

(d) In the case of the CPT as (c) above but for soil identification in connection with key borings

(e) Investigation of earrelations between different penetration testing methods

f) Review the application of the various methods to the prediction of engineering behaviour (hearing capacity and settlement) and identify the limitations of the various penetration testing methods

The committee has got an invitation from the British Geotechnical Society (BGS) in which BGS express its willingness to serve as hast society for TC 16 during the next four years period Also the societies in France and The Netherlands have expressed similar interest The British Geotechnical Society has proposed Eugene Toolan and Chris Clayton as chairman and Secretary respectively

Respectfully submitted

Mr P Abbona Argentina Mr C Arce Argentina Dr J C Halden Australia Prof E De Beer Belgium Mr E H G Gaelen Belgium Prof A van Wambeke Belgium Dr L Decourt Brazil Mr A H Teixeira Brazil Prof G Stefanoff Bulgaria Dr R G Campanella Canada Ing A Bacmanakova Czechoslovakia Dr H Denver Denmark Dr K J Melzer FRG Prof M Tammirinne Finland Mr S Amar France Prof F Baguelin France Mr L Parez France Prof G Sanglerat France Dr B Kralik Hungary Dr M D Desai India Prof A Komornik Israel Prof J G Zeitlen Israel Prof E Zolkov Israel Prof M Jamiolkowski Italy Dr T Muromachi Japan

4

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

Mr W J Heijnen Netherlands co-chairman Mr K Joustra Netherlands Mr T Lunne Norway Dr K Senneset Norway Mr I Saeed Pakistan Mr G A Jones South Africa Dr K W Lo south East Asia Mr U Bergdahl Sweden chairman Dr E Sellgren Sweden secretary Mr B A Leach United Kingdom Mr I K Nixon United Kingdom Mr S Thorburn United Kingdom Prof J Osterberg USA Prof J H Schmertmann USA Mr Y G Trofimenkov USSR

5

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

APPENDIX A

INTERNATIONAL REFERENCE TEST PROCEDURE FOR CONE PENETRATION TEST (CPT)

l SCOPE

The cone penetration test consists of pushing inta the soi l at a sufficiently slow rate a series of cylindrical rads with a cone at the base and measuring in a continuous manner or at selected depth intervals the pene tration resistance on the cone and if required the total penetration resistance andor the local side frie tian resistance on a frietian sleeve In addition the pore-water pressure present at the interface between penetrometer tip and soil can be measured during penetration by means of a pressure sensor in the cone This pore-water pressure includes the pore-water pressure increase or decrease due to compression and dilation of the saturated soil around the cone arising from the penetration of the cone and the push rads inta the ground

Cone penetration tests are performed in order to obtain data on one or more of the following subjects

l The stratigraphy of the layers and their homogenity over the site

2 The depth to firm layers the location of cavities voids and other discontinuities

3 Soil identification 4 Mechanical soil characteristics 5 Driveability and bearing capacity of piles

2 DEFINITIONs

21 CPT stands for Cone Penetration Test and includes what has been variously called Static Penetration Test Quasi-Static Penetration Test and Dutch Sounding Test

22 Penetrometer An apparatus consisting of a series of cylindrical rads with a terminal body called the penetrometer tip and the measuring devices for the determination of the cone resistance and one or more of the fo llowing characteristics the local side frietian resistance the total resistance the pore-water pressure present in the immediate vicinity of the cone during penetration

23 Penetrometer tip The terminal body with a l ength of 1000 mm at the end of the series of push rads which comprises the active e lements that sense the cone resistance the local side-frietian resistance and the pore-water pressure present at the interface of cone (definition see seetian 3 2 and soil during penetration

2 31 Shaft The cylindrical part of the penetrometer tip above the cone andor the frietian sleeve

24 Cone The cone-shaped end piece of the penetrometer tip on which the end hearing is developed

2 4 1 According to the degree of freedom of the cone the following types are defined

fixed cone penetrometer tip Where the cone can only be subjected to micro-displacements relative to the other elements of the tip free cone penetrometer tip Where t he cone can move freely with respect to the other elements of the tip

242 According to the shape of the cone the following are defined

Simple cone A cone having a cylindrical extension above the conical part with a length considerably smaller than the diameter of the cone Mantle eone A cone which is extended with a fixed more or less cylindrical sleeve of which the diameter is smaller than the diameter of the cone and with a length 1 to 3 times the cone diameter this sleeve is called the mantle

243 Piezo-eone A cone with a filter inserted in the conical part or in the cylindrical extension of the cone (see definition seetian 32 to measure the poreshywater pressure present in the soil during penetration by means of a pore- water pressure sensor

25 Frietian sleeve The seetian of the pe netrometer tip upon which the local side frietian resistance to be measured is developed

2 6 System of measurement The system includes the measuring deviees themselves and the means of transmitting information from the tip to where it can be seen or recorded For example the following can be defined

261 Eleetric penetrometer Which uses electrical devices such as strain gauges vibrating wires etc built inta the tip

2 62 Meehanieal penetrometer Which uses a set of inner rods to operate the penetrometer tip

26 3 Hydraulic and pneumatic penetrometer Which uses hydraulic or pneumatic devices built inta the tip

2 7 Push rods The thick-walled tubes or solid rods preferably with a length of l metre used for advancing the penetrometer tip

2 8 Inner rods Solid rads which slide inside the push rods to extend the tip of a mechanical penetrometer

29 Thrust maehine The equipment that pushes the penetrometer into the soil The necessary reaction for this rnachine is obtained by dead weight and or anchors

210 Frietian redueer Narrow local protuberances outside the push rod surface placed above the penetrometer tip and provided to reduce the total frietian on the push rads

6

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

211 Continuous and discontinuous tests (see Note 1

2111 Continuous penetration test A penetration test in which the cone resistance is measured while all elements of the penetrometer have the same rate of penetration

2112 Discontinuous penetration test A penetration test in which the cone resistance is measured while the other parts of the penetrometer tip remain stationary When a friction sleeve is also included the sum of the cone resistance and local side frietian resistance is measured when both cone and frietian sleeve are pushed down together while the other parts of the penetrometer tip remain stationary

212 Cone resistance qc The cone resistance qc is obtained by dividing the ultimate axial force acting on the cone Qc by the area of the base of the cone Ac

A c

This resistance is expressed in MPa or kPa

213 Local unit side friction resistance f s The local unit side frietian resistance is obtained by dividing the ultimate frictional force Qs acting on the sleeve by its surface area As

The local unit side frietian resistance f is s

expressed in Pa kPa or MPa

214 Total force Qt The force needed to push cone and push rads tagether inta the soil Qt is expressed in kN

215 Total side friction resistance Qst This is generally obtained by subtracting the ultimate force on the cone Qc from the total force Qt

Qst is expressed in kN as are Qt and Qc

Certain penetrometers allow Qst to be measured directly

216 Friction Ratio Rf and Frietian Index If (see Nate 2)

2161 Friction Ratio Rf The ratio of the local unit side frietian resistance f to the cone

s resistance qc measured at the same depth expressed as a percentage

2162 Friction Index If The ratio of the cone resistance qc to the local unit side frietian resistance fs measured at the same depth

3 REFERENCE TIST PENETROMETER AND EQUIPMENT

31 General geometry of the penetrometer tip In the reference penetration test penetrometer tips with or without a frietian sleeve and with or without a porewater pressure meter may be used If a gap between the cone and the other elements of the penetrometer tip exists it shall be kept to the minimum necessary for the operation of the sensing devices and designed and constructed in such a way as to prevent the entry of particles (see Nate 3 This shall also apply to the gaps at either end of the frietian sleeve if one is included and to the other elements of the penetrometer tip The axes of the cone the frietian sleeve if included and the body of the penetrometer tip shall be coincident

The diameter of the shaft of the penetrometer tip shall nowhere be less than 03 mm smaller nor more than l mm greaterthan the nominal diameter of 357 mm of the reference cone

In addition in the case of a penetrometer tip with a frietian sleeve no part of the penetrometer tip shall project beyond the sleeve diameter An example of a reference penetrometer is presentad in Fig l (a) and (b)

sea

shaf t of the

2Aglt 10 mm

l referred to one s1de of the crossshysectional area )

l c)

sea

sleeve

watertight sea

l b )

Fig l ExampLe of a reference penetrometer with a fix ed cone and (a) without of (b) with frietian sLeeve DetaiL of gap (c)

7

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

32 Cone The cone shall consist of a conical part and a cylindrical extension (Fig 2) the apex angle of the cone shall be 60deg

t-----~=tmmlt bull W mm

Z40mm ~hc ~31Zmm surfac~ roughn~ss

~1 Mm l

Fig 2 ToLerances on the dimensions of the reference cone

For the reference cone the length he of the cylindrical part directly above the conical part shall not exceed 10 mm

This also holds for the piezo-cone with the filter element in the cylindrical extension (Fig 3 )

f i l t~r

Fig 3 Piezo-cone with a fiLter eLement in the cyLindricaL extension

2The area A of the base of the cone shall be 1000 mm c

givinga cone diameter of 357 mm Cone diameter is defined as the diameter of the cylindrical extension

The surface roughness in the longitudinal direction of the cone shall not exceed l 11m which is equivalent to the roughness produced by the frietian of the soil Tolerance on the dimensions (see Nate 4)

(a) On the area of the base of the cone Ac

2A 1000 mm - 5 + 2 c

giving a cone diameter dc

348 mm lt d lt 360 mm c

For a worn tip the cone diameter shall be measured across the top seetian of the cylindrical extension

(b) on the height hc of the conical part of the cone

24 0 mm lt h lt 312 mm c

(c) on the height hc of the cylindrical extension

7 mm ~ he ~ 10 mm

Cones with a visible asymmetrical wear are to be rejected

3 3 Gap and seal above tbe cone (Fig l) The gap between the cone and the other elements of the penetroshymeter shall not be greater than 5 mm

The outer limits of the gap shall be shaped in such a way that the measurement cannot be affected by possible bridging by soil particles The seal placed in the gap shall be properly designed and manufactured to prevent the entry of soil particles inta the penetrometer t i p It shall have a deformability many times larger than that of the sensing devices inside the tip The cross- sec t i onal area A of the gap remaining after deduction of the area o~cupied by the seal shall be less than 10 mm 2

(Fig l)

3 4 Sensing devices The sensing devi ces f or measuring the cone resistance and the frietian r es i stance shall be designed in such a way that eccentricity of these resistances cannot influence the readings The sensing device for the local frietian resistance shall operate in such a way that only the shear stresses and not normal stresses acting on the frietian sleeve are recorded

35 Frietian sleeve (Fig lb) The diameter of the frietian sleeve shall not be less than the actual diameter of the base of the cone the surface area of the

2104frietian sleeve shall be 15 x mm bull

Tolerances on the dimensions (a) on the diameter d of the frietian sleeve

s

d lt d lt d + o 35 mm c s c

dc being the actual diameter of the base of the cone

(b) on the surface area A of the frietian sleeve s

2A 15xl04 mm +2 -2 ie s

2A lt l 53xl04 mm s

(c) on the surface roughness r of the frietian sleeve in the direction of the longitudinal axis (see Nate 5)

025 11m (r ( 075 11m

The frietian sleeve shall be located immediately above the cone (Fig lb) The gaps between the frietian sleeve and the other parts of the penetrometer tip and their seals shall conform to the requirements of Section 3 3

36 Push rads The push rads shall be screwed or attached tagether to hear against each other and to form a rigid-jointed series with a continuous straight axis The deflection (from a straight line through the ends) at the mid-point of a l m push rad shall not exceed (i) 0 5 mm for the five lowest push rads and (ii) l mm for the remainder

8

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

For any pair of joined push rads the deflection (from a straight line through the mid-points of the rads) at the joint shall also not exceed these limits

37 Measuring equipment The resistances on the cone and the frietian sleeve if included and the pore-water pressure in case of a piezo-cone shall be measured by suitable devices and the signals transmitted by a suitable method to a data recording system Recording test data exclusively on a tape which does not permit direct accessibility during the test is not recommended

38 Trust machine The rnachine shall have a strake of at least one metre and shall push the rads inta the soil at a eonstant rate of penetration The thrust rnachine shall be anchored andor ballasted such that it does not move relative to the soil surface during the pushing action

39 Frietian reducer If a frietian reducer is included it shall be loacted at least 1000 mm above the base of the cone

4 TESTING PROCEDURE

41 Continuous test The testing procedure shall be that of continuous penetration testing in which the measurements are made while all elements of the penetrometer tip have the same rate of penetration

42 Verticality The thrust rnachine shall be set up so as to obtain a thrust direction as near vertical as practicable The deviation from vertical of the thrust direction shall not exceed 2 The axis of the push rads shall coincide with the thrust direction

43 Rate of penetration The rate of penetration shall be 20 mmsee with a tolerance of ~5 mm see In case of a piezo-cone this tolerance shall be narrowed Between these tolerances a eonstant rate shall be maintained during the entire strake even if readings are taken only at intervals

44 Interval of readings A continuous reading is recommended In no case shall the interval between the readings be more than 02m

45 Measurement of the depth The depths shall be measured with an accuracy of at least 0 1 m

5 PRECISION OF TIIE MEASUREMENTS

Taking inta account all possible sources of error (parasitic frictions errors of the measuring devices eccentricity of the load on the cone with respect to the sleeve temperature effects etc ) the precision of measurement shall not be worse than the following whichever is the greater

5 of the measured value l of the maximum value of the measured resistance in the layer under consideration

The precision shall be verified in the laboratory or in the field taking inta account all possible disturbing influences (see Nate 6)

6 PRECAUTIONS CHECKS AND VERIFICATIONS

61 Straightness of push rods Regular checks shall be made on the straightness of the push rads and their joints particularly for the lowest five rads of the series (see par 36 and Nate 7)

62 Wear Regular inspections shall be made for wear of the cone frietian sleeve and shaft of the penetrometer tip

63 Distance to other tests The CPT shall not be performed too close to existing boreholes or other penetration tests It is recommended that reference deep CPTs shall not be performed closer than 25 boring diameters from boreholes or at least 2 m from previously performed CPTs (see Note 8)

64 Seals The seals between the different elements of a penetrometer tip shall be regularly inspected to determine their condition Prior to use the seals shall be checked for the presence of soil particles and cleaned

65 Temperature compensation Electric penetrometer tips shall be temperature compensated If the shift observed after extracting the tip is so large that the precision defined under Section 5 is no longer met the test shall be discarded as reference test

7 CALIBRATION

71 Manometers Manometers shall be calibrated at least every 6 months For each type of manometer there shall be two identical units each with its own calibration available with the machine At regular intervals the manometer used in the tests shall be checked against the reserve manometer

72 Load cellsproving rings Load cells or proving rings shall be calibrated at least every 3 months Regular checks on the site with an appropriate field control unit are recommended

8 SPECIAL FEATIJRES

81 Push rod guides In order to prevent buckling guides shall be provied for the part of the push rads protruding above the soil and for the push rod length in water

82 Inclinometers In order to obtain more precise information on the drift of the push rads in the soil inclinometers may be built into the penetrometer tip

The need for such information depends on the soil conditions and increases with increasing depth of the test

83 Push rods with smaller diameters In order to decrease the skin friction on the rods use may be made of push rads with a smaller diameter than that of the penetrometer tip The distance between the smaller diameter push rads and the cone base shall be at least 1000 mm

9

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

84 Piezo-cone The tip may be equipped with a pore-water pressure sensing device connected to a filter placed in the conical part or on the cylindrical part of the cone (see Nate 9) The filter and all fluid spaces of the piezo-cone shall be filled with water or another suitable fluid and thoroughly deaired before each set of tests Preeautians shall be taken to maintain full saturation of the filter and the other spaces of the measuring system during transport to the test site and during the execution of the piezo-cone penetration tests especially when the upper layers of the ground are not saturated

9 REPORTING OF RESULTS

The results shall be reported on graphs giving in function of the depht the variation of qc and eventually fs Rf (If) andor Qt and or Qst andor u

9 l The following information shall be reported

- on the graphs of the test results

l Where the penetrometer and the test proeecture are completely in agreement with the reference proeecture each graph shall be marked with the letter R (~eference test procedure) One of the following letters shall be added to indicate the system of measurement

M mechanical E electrical H hydraulic

The capacities of the different measuring devices of the penetrometer tip shall be reported

2 The date and time of the test and the name of the firm

3 The identification of the CPT and the location of the site

4 The depth over which a frietian reducer or push rads with a reduced diameter has been used The depth at which the push rads have been partly withdrawn in order to reduce the side frietian resistance and thus achieve greater penetration depth

5 Any abnormal interruption of the reference proeecture of the CPT even as all interruptions in case of a piezo-cone

on the graphs or in the report

6 Observations made by the operator such as soil type sounds from the push rads indications of stones disturbances etc

7 Data concerning the existence and thickness of fill or existence and depth of an excavation and starting level of the CPT with respect to the original or modified soil surface

8 The elevation of the soil surface at the location

of the test 9 If a piezo-cone is used a clear indication of

the position the size and the material of the filter 10 The readings of the inclinometer if taken 11 The zero readings of all sensors before and after

the test 12 All checks made after extracting the push rads

the condition of the push rads and the penetrometer tip

13 The depth of the water in the hale remaining after withdrawal of the penetrometer or the depth at which the hole collapsed

14 Whether or not the test-hale has been backfilled and if so by which method

92 Besides the information indicated in Section 91 the intemal files shall also record

l The identification of the penetrometer tip used 2 The name of the operator in charge of the crew

which performed the test 3 The dates and reference numbers of the calibration

certificates for the measuring devices

93 It is recommended to use the following relationship between the scales on the vertical and harizontal axes

Depth scale vertical axis l unit length (arbitrary) for l m

Cone resistance qc harizontal axis the same unit length for 2 MPa

Local side frietian resistance f harizontal axis s

the same unit length for 50 kPa

Total penetration force Qt harizontal axis the same unit length for 5 kN

Total frietian Qst harizontal axis the same unit length for 5 kN

Pore-water pressure harizontal axis the same unit length for 20 kPa

As only values for the scale ratios are recommended the unit length on the vertical axis may be ehosen arbitrarily in such a way that standard sheets can be used (see Fig 4)

9 4 Site plan

For every investigation which is carried out a clear si te plan shall be drawn with clear reference points in order that the locations of the penetrometer tests can be plotted accurately Also when made in conjunction with borings the time sequence of the borings and CPTs shall be indicated

lO

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

- CONE RESISTANCE IN MPbull LOCAL FRICTION f s IN MPbull ~RICTION R~TIO R t IN ~bull 60 0 0 02 0440middot10 o 20 middot10 t-- --t------1 middot10

--- PORE WA HR 02 04 06

PRESSURE in MPbull

Q

bullz o 8 -10 a shy shya E

~

I Q

~ -201-l~----

-30 1---------- shy

zero-reading

DELFT GEOTECHNICS

WONINGEN TE MAASSLU5 CONE PENETRA TON TES T

-30

Remarks frietian reducer not ~ppleid

of thbull cone abnormil inte rr uptions none observations no special obier vat 1ons

~~~-----------=-----==-- f1llexcavation old filt 4m thickness c--t~~c---linctinometer

condition of waterlevet backfillmq precision

dbulltbull of test 87-02-19 time 14-15 hrsGO 021RE

lO DEVIATIONS FROM TIIE REFERENCE TIST

101 General

All deviations from the Referenee Proeedure shall be deseribed explieitely and eompletely on the graphs with the test results

The different possible deviations are

102 deviation of the eone dimension

103 deviation of the apex angle of the eone

104 deviation of the frietian sleeve dimensions

105 deviation of the loeation of the frietian sleeve

106 deviation related to th~ shape of the penetrometer tip

107 deviation related to the possibility of relative movements of the eone with respeet to the push rods (so ealled free penetrometer tips)

11

no readings taken push radspenetrometer t 1p after test good

in sounding hol e hol e collapsed neu surface none of the measuring devices

102 Deviation of the eone dimension

In eertain eireumstanees it may be neeessary to deviate from the Referenee Test Proeedure by adapting smaller or l a rger eone diameters All toleranees speeified for the Referenee Test shall be adapted in direet proportion to the diameter

103 Deviation of the apex angle

It may be neeessary to deviate from the apex angle of the eone smaller or larger than 60deg Examples of penetrometers using eones with deviating diameters and deviating apex angle are given in Fig 5 and Fig 6 assuming for Fig 6 that the test is run in a eontinuous testing manner

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

point resistance [ point resistance ljCItrpc=shy

6 1---total side local smiddot1de

f ric t i on fri et i onl

t otal sideJ friction

frielien sleeve

friction sleeve

l 900

lt139 mm l

f--bullbull_al 80 m m ___-o_ao m m

Fig 5 (a) the Andina eone penetrometer tip and (b ) the frietian sleeve eone penetrometer tip

-friction sleeve

l l ~ ats mm middotmiddot----4 5 m m _~r----+

Fig 6 (a) the Parez hydraulie penetrometer tip and (b) the frietian sleeve hydraulie penetrometer tip

104 Deviation of the frietian sleeve dimensions

If the length of the frietian sleeve of a penetrometer havinga cone diameter of 357 mm deviates fromthat of the Reference tip then the surface area of the sleeve

2A should not be larger than 35x104 mm and not s~aller than lx104 mm 2

bull

In the case of a cone diameter different from 357 mm the surface area of the sleeve shall be adjusted proportioshynally with respect to the cross sectional area of the cone

105 Deviation of the location of the frietian sleeve

The distance between the base of the cone and the lower end of the frietian sleeve can be larger than that corre shysponding to the reference tip An example of penetrometer tip with a location of the sleeve which deviates from the reference is given in Fig 7

Fig 7 The Degebo frietian sleeve eleetric penetrometer tip

106 Deviation related to the shape of the penetrometer tip

In certain circumstances special electrical penetrome t e r tips with a shape deviating from the Reference Test are used An example is given in Fig 8

frietian sleeve

i=

E

E o o

E M l E

i28mm o o

ZS 28mm N

l

T

__bmm 356 mm

Fig 8 The Delft eleetrie penetrometer tip (a) without and (b) with a frietian sleeve

12

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

107 Deviation related to the possibility of relative movements of the cone with respect to the push rods (so called free cone penetrometer tips)

With a free cone penetrometer tip testing in either continuous or discontinuous manner is possible (see note 10) In the case of a test run in a discontinuous manner although the rate of down-ward movement due to the thrust rnachine is known the rate of penetration of the cone at the point of rupture of the soil can be different from that of the movement due to the thrust machine They earrespond only when there is continuous downward movements of the push rods

108 Symbols and indications

Only the test performed according to the Reference Test Proeecture can be represented by the letter R (see Section 91) In case of deviations besides their explicit deshyscription on the graphs also the indications M (Mechanishycal) E (Electrical or H (Hydraulic) can be added as an indication of the measuring system in accordance with Section 91

109 Mechanical penetrometer - Precautions checks and verifications

1091 Push rods

There shall not be any protruding edge on the inside of the push rods at the screw connection between the rods (Fig 9)

Fig 9 Not acceptable protruding edge at the screw connection rads

When testing in a discontinuous manner the minimum movement of the cone or the friction sleeve shall be 05 timesthe cone diameter (see Note 11)

Examples of free cone penetrometer tips in use in many countries are presented in Fig 10 11 12 13 and 5 if used in a discontinuous testing manner (see Note 12)

E Il

ugt

E E l()

~ 23m m

E E

N

ltP 14m m

E E Q27mm

o N

E E mantie

G

cl 3 7

Fig 10 The Dutch mantle cone penetrometer tip

~35mm

~15mm

rgt 30mm

iJ 20mm

E E

Ilgt l

Fig 11 The Dutch frietian sleeve penetrometer tip

13

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

bull Note 11 Discontinuous test 107)

In the case of mechanical penetrometer tips in order to be certain that the cone and the frietian sleeve move sufficiently with respect to the push rods due account shall be taken of the elastic shortening of the inner rods Therefore at the surface the movement of the inner rods relative to the push rods shall be at least equal to the sum of the minimum imposed movement of the cone (see Section 109) plus the shortening of the inner rods

bull Note 12 Simple cone 107 Fig 12)

In the case of the simple cone special preeautians shall be taken against soil entering the sliding mechanism and affecting the resistance measurements After extracting the penetrometer tip a check shall be made in order to be certain that the cone stem still moves completely free relative to the bush

16

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

APPENDIX B

INTERNATIONAL REFERENCE TEST FOR THE STANDARD PENETRATION

l SCOPE

11 This document describes the principles constituting acceptable test proeectures for the SPT from which results are comparable

12 The SPT determines the resistance of soil at the base of a borehole to the penetration of a tubular steel sampler and permits the recovery of a disturbed sample for identification The penetration resistance can be related to the characteristics and variability of soils

The basis of the test consists of dropping a hammer weighing 635 kgf on to a drive head from a height of 760 mm The number of blows (N) necessary to achieve a penetration by the sampler of 300 mm (after its penetration under gravity and below a seating drive) is regarded as the penetration resistance (N)

2 DEFINITIONs

21 SPT is the abbreviation for the standard pene tration test as described in this reference test procedure

22 Sampler A tubular steel assembly having the components described in Section 32

23 Drive rods Steel rods connecting the sampler to the drive head

24 Hammer assembly The items of equipment which are used to drive the sampler into the soil and which comprise a drive head a hammer a guide and release mechanism

25 Drive head A steel anvil attached to the top of the drive rods by screw threads This anvil is an interna part of some hammer assembl ies known as safety hammers In this case the rod coming from the assembly is screwed on to the drive rods

26 Hammer A steel body of 635 kgf weight

27 Guide A steel rod to guide the hammer smoothly through a free fall of 760 mm

28 Release mechanism A mechanical release device to ensure that the hammer has a eonstant free fall of 760 mm

29 Seating Drive The number of blows required for the initial penetration of the sampler of 150 mm

210 Test drive The number of blows after the seating drive required for an additional penetration of 300 mm

PROCEDURE TEST (SPT)

3 EQUIPMENT

31 Boring equipment

311 The boring equipment shall be capable of providing a clean hole to ensure that the penetration test is performed on essentially undisturbed soil

312 When wash boring a side-discharge bit shall be used and not a bottom- discharge bit The process of jetting through an open tube sampler and then testing when the desired depth is reached shall not be permitted

313 When us ing shell and auger boring methods with temporary casing the drilling tools shall have diameters not more than 90 of the interna diameter of the casing

314 The diameter of the borehole shall be as small as practicable and shall be between 63 and 150 mm

32 Sampler

The tube of the sampler shall be made of hardened steel with smooth interna and externa surfaces The externa diameter shall be 51 mm plus or minus l mm and the interna diameter throughout shall be 35 mm plus or minus l mm Its length shall be 457 mm minimum

The lower end of the tube shall have a drive shoe 76 mm long plus or minus l mm having the same bore and externa diameter as the tube Over the lowermost 19 mm the drive shoe shall taper uniformly inwards A sharp cutting edge should be avoided as shown on Fig l The material shall be the same as that of the tube

At the upper end of the tube a steel eaupling shall be fitted to connect with the drive rods Inside shall be a non-return valve with wide vents in the eaupling wall which are of sufficient size to permit unimpeded escape of air or water on entry of the sample The valve shall provide a watertight seal when withdrawing the sampler

The drive shoe shall be replaced when it becomes damaged or distorted and the sampler shall be clean and free from soil encrustation internally and externally

One acceptable form of the sampler is shown in Fig l

mm ~~~bVEE --1 1-- COUPUNG ~ 19 T i+ --r1SPLIT SAFIREL l

middotmiddot~tclc(~~~~Jl ~ _J- 57mm(monomum ) -)j _JL 76mm ~ 152mm

Fig 1 Cross seetian of SPT sampLer

17

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

33 Drive rods

331 The steel drive rods connecting the sampler to the drive head shall have a section modulus appropriate to their total length and lateral restraint

Appropriate section properties are

Rod Diameter Section Modulus Rod Weight 3(mm (x 10- 6 m (kgfm

405 428 433 50 859 723 60 1295 1003

Rods heavier than 1003 kgfm shall not be used

332 Only straight rods shall be used and periodic checks shall be made on site When measured over the whole length or each rod the relative deflection shall not be greater than 1 in 750

333 The rods shall be tightly coupled by screw joints

34 Hammer assembly

341 The hammer assembly shall comprise

a A steel drive head tightly screwed to the top of the drive rods It can be an interna part of the assembly as with safety hammers The energy transferred on impact shall be maximised by a suitable design of drive head

412 When boring below the groundwater table the surface of the water or drilling fluid in the borehole shall at all times be maintained at a sufficient distance above the groundwater level to minimise disturbance The level of the water or drilling fluid in the borehole shall be maintained during withdrawal of the boring tools and throughout the test to ensure hydraulic balance at the test elevation

413 The drilling tools eg the shell shall be withdrawn slowly to prevent suction effects eausing laosening of the soil to be tested

414 When casing is used it shall not be driven below the level at which the test is to commence

42 Execution of test

421 The sampler shall be lowered to the bottom of the borehole on the drive rods with the hammer assembly on top The initial penetration under this total deadweight shall be recorded Where this penetration exceeds 450 mm the test drive will be omitted and the N value taken as zero

After the initial penetration the test will be executed in two stages

Seating Drive The sampler shall be driven to a depth of penetration of 150 mm into the soil and the number of blows to achieve this penetration shall be recorded If the 150 mm penetration cannot be achieved in 50 blows the depth of penetration achieved after 50 blows shall be taken as the seating drive In this case the depth shall be recorded

b A steel hammer of 635 kgf plus or minus 05 kgf weight

c A guide to ensure that the hammer drops with minimal resistance

d A mechanical release mechanism which will ensure that the hammer has a eonstant free fall of 760 mm

3 42 The overall weight of that part of the hammer assembly that rests on the drive rods shall not exceed 115 kgf

343 In situations where comparisons of SPT results are important calibrations shall be made to evaluate the effici ency of the equipment in terms of energy transfer In such cases N val ues shall be adjusted by calibration to a reference energy of 60 per cent of the nominal kinetic energy in a 635 kgf hammer after free fall of 760 mm namely 474 Joules The reference energy shall be measured immediately below the drive head

4 TFST PROCEDURE

41 Preparation of borehole

411 The borehole shall be carefully cleaned out to the test elevation using equipment that will ensure the soil to be tested is not disturbed When boring in soils that will not allow a hole to remain stable casing andor bentonite drilling fluid shall be used Hollow stem auger casing shall not be used for tests below groundwater

Test Drive The number of blows required for subsequent 300 mm penetration is termed the penetration resistance (N The number of blows required to effect each 150 mm of penetration shall be recorded The test drive may be terminated after 50 blows in either of the 150 mm increments The number of blows shall be recorded for each 150 mm increment or the depth of penetration achieved shall be recorded if the test is terminated at 50 blows

The rate of application of hammer blows shall not be excessive such that there is the possibility of not achieving the standard drop or preventing equilibrium conditions prevailing between successive blows Typically the maximum rate of application of blows is 30 per minute

4 3 Recovery of soil sample and labelling

4 31 The sampler shall be raised to the surface and opened The representative sample or samples of the soil in the sampler shall be placed in an air-tight container

432 Labels shall be fixed to the containers with the following information

a Site b Borehole number c Sample number d Depth of penetration e Length of recovery f Date of test g standard penetration resistance (N

18

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

5 REPORTING OF RFSULTS

The following information shall be reported

l Site 2 Date of boring to test elevation 3 Date and time of commencement and end of test 4 Borehole number 5 Boring method and diameter of base of borehole and

whether it contained water or drilling fluid 6 Dimensions and weight of drive reds used for the

penetration tests The weight of drive head also shall be stated

7 Type of hammerand release mechanism 8 Height of free fall 9 Depth to bottom of borehole (before test) 10 Depth to bottom of casing 11 Information on the groundwater level and the leve of

water or drilling fluid in the borehole at the start of each test

12 The depth of initial penetration and the depths between which the penetration resistances (seating and test drives) were measured

13 The number of blows required for each successive 150 mm increment of penetration (for the seating drive and for the test drive) eg 121516 The depth of penetration achieved shall be reported if the test is terminated at 50 blows eg 204550 - 100 mm or 3050 - 75 mm

14 The descriptions of soils as identified from the samples in the sampler

15 Observations concerning the stability of strata tested or obstructions encountered during the tests etc which will assist the interpretation of the test results

16 Results of calibration tests where appropriate (Clause 3 43)

6 APPENDIX

Deviations from the reference test

(i) The document entitled Standard Penetration Test (SPT) International Reference Test Procedure and presented by the Working Party at ISOPT-1 Orlando USA March 20-24 1988 identified variations in equipment and proeectures evolved by the member countries of the ISSMFE

(ii) The variations listed below are indicative of the current situation and trends

a The interna diameter of the barrel of the sampler being 3 mm greater than the standard 35 mm interna diameter of the drive shoe (USA)

b The use of a solid steel cone in lieu of the standard drive shoe for tests in gravels and weak rocks (United Kingdom FRG and Austrashylia)

c The elimination of the influence of the drive reds by means of a hammer positioned immediately above the sampler (M E Schultze 1961) Contributian to discussion proc 5th Int Conf of ISSMFE Paris Vol III p183

19

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

APPENDIX C

INTERNATIONAL REFERENCE TEST PROCEDURES FOR DYNAMIC PROBING (DP)

l SCOPE After proper calibration the results of dynamic probing can be used to get an indication of such engineering

The expression probing is used to indicate that a properties as eg continuous record is obtained from the test in contrast relative density to for example the Standard Penetration Test SPT) The compressibility aim of dynamic probing is to measure the effort required shear strength and to drive a cone through the soil and so obtain resistance consistency values which earrespond to the mechanical properties of the soil Four proeectures are recommended For the time being quantitative interpretation of the

results including predietians of hearing capacity remains Dynamic probing light DPL) representing the lower restricted mainly to cohesionless soils it has to be end of the mass range of dynamic penetrometers used taken into account that the type of cohesionless soil worldwide the investigation depth usually is not larger (grain size distribution etc) may influence the test than about 8 m if reliable results are to be obtained results

Dynamic probing medium (DPM) representing the medium mass range the investigation depth usually is not 22 Classification larger than about 20 to 25 m

Four different probing methods types DPL DPM DPH and Dynamic probing heavy (DPH) representing the medium DPSH are recommended to fit different topographic and to very heavy mass range the investigation depth usually geological conditions and various purposes of investigashyis not larger than about 25 m tion Apparatus test procedures measurements and recorshy

ding are described in the following Sections Technical Dynamic probing superheavy DPSH) representing the data are summarized in Table l Other types of equipment upper end of the mass range of dynamic penetrometers and may be required for special purposes or different cone simulating closely the dimensions of the SPT the dimensions (see Section 9) investigation depth can be largPr than 25 m

3 bull EQUIPMENT

2 DEFINITIONS 31 Driving Device

21 General Principles and Nomenciature The driving device consists of the hammer the anvil and

A hammer of mass M and a height of fall H is used the guide rod Dimensions and masses are given in Table to drive a pointedprobe (cone)The hammerstrikes an l

anvil which is rigidly attached to extension rods The penetration resistance is defined as the The hammer shall be provided with an axial hole with a number of blows required to drive the penetrometer a diameter which is about 3-4 mm larger than the diameter defined distance The energy of a blow is the mass of the of the guide rod The ratio of the length to the diameter hammer times the acceleration of gravity and times the of the cylindrical hammer shall be between l and 2 The height of the fall (MxgxH) The results of different hammer shall fall freely and not be connected to any

types of dynamic probing may be presented (andor object which may influence the acceleration and

compared) as resistance values qd or rd (see deceleration of the hammer The velacity shall be Note l Section 10) negligible when the hammer is released in its upper

position (see Section 6)

Dynamic probing is mainly used in cohesionless soils In interpreting the test results obtained in cohesive soils The anvil shall be rigidly fixed to the extension rods

and in soils at great depths eautian has to be taken The diameter of the anvil shall not be less than 100 mm

when friction along the extension rod is significant see and not more than half the diameter of the hammer The

seetian 7 Dynamic probing can be used to detect soft axis of anvil guide rod and extension rod shall be

layers and to locate strong layers as for example in straight with a maximum deviation of 5 mm per meter

cohesionless soils for end-hearing piles DPH DPSH) In connection with key borings soil type and cobble and boulder contents can be evaluated under favourable conditions The results of the DPL can also be used to evaluate trafficability and workability of soils

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

--

Table l Technical data of the equipment

Reference Tist P rocedu reFactor DPL DPM DPH OPSI

plusmnHammer mass kg 1 D D l 3D o 3 50 bull o 5 63 5 o 5

Height of fall m 0 5 plusmn 0 0 1 o 5 plusmn o o 1 0 5 plusmn o o 1 D 7 5 plusmn o 02

Mass of an vi l and 6 18 18 30 g u ide rod (max J kg

Re bo und (max) 50 50 50 50

Length to d i umeter l Dl )l lt2 gtl 2 ~ 2 gt l bull 2 rati o ( hammer l

Di ameter of anvil Id l mm 1 O O cd ltO 50 1QQ (dlt O 50 1 OO lt d ltO 50 100ltdlt05D

Ro d length m 1 plusmn o l 1-2 plusmn o 1 1-2 plusmn o 1 1-2 plusmn o 1

Maximum mass of rad kgm 3 6 6 8

Rod deviation (max l o 1 o l o l o l first 5 m

Ro d deviation (max) 0 2 D 2 o 2 0 2 below 5 m

Ro d eccentr i city (max) mm o o 2 D 2 o 2 D 2

Ro d OD mm 22 plusmn o 2 32 plusmn 0 3 32 plusmn o 3 32 plusmn 0 3

Ro d ID mm 6 o 2 9 plusmn 0 2 9 plusmn o 2 shy

Apex an g le deg 90 90 90 90

Bas e area of cone cm2 l o 1 o 15 20

Cone diameter new mm 35 7 plusmn D 3 35 7 plusmn o 3 43 7 plusmn 0 3 5 l plusmn 0 5

Con e di am (min) worn mm 34 34 42 49

Man t le lengtl1 of cone mm 3 5 7 plusmn 1 35 7 plusmn l 43 7 plusmn l 5 l plusmn 2

Cone tape r a ng le Il Il Il Il upper deg

Length of con e t i p mm l 7 9 plusmn o 1 17 y plusmn o l 2 l 9 t o l 25 3 t o 4

max wear of con e tip length mm 3 3 4 5

Number of blows l o cm NIO 1 O cm N1 0 lO cm NI O 20 cm N2o per cm penet ra tio n

standard rang e of blows 3 - 50 3 - 50 3 - 50 5 - l 00

Specif i c work per blow 50 150 l 67 238 Mg H A kJm2 l

32 Extension Rods

Dimensions and masses of the extension rads are given in Table l The rod material shall be of high-strength steel with high resistance to wear have a high toughness at low temperatures and a high fatigue strength Permanent deformations must be capable of being corrected The rads s hall be straight Solid rads can be used hollow rads should be preferred in order to reduce the weight (see Section 7 The rod joints shall be flush with the rods (see Section 6)

33 Cones

Dimensions of cones are given in Table l The cone consists of a conical part (tip) a cylindrical extension and a conical transition with a length equal to the diameter of the cone between the cylindrical extension and the rod (Fig l) The cones when new shall have a tip with an apex angle of 90deg

010

Fig l Scheme of cones and rads (for dimensions see Table l D = cone diameter)

21

The maximum permissible wear of the cone is given in Table l The cone shall be attached to the rod in such a manner that it does not laosen during the driving Fixed or lost (detachable cones can be used

4 TEST PROCEDURE

41 General

Criteria for the purpose of a test should be specified in advance The depth required will depend on the local conditions and the purpose of the particular test

42 Probing Equipment

Probing shall be effected vertically unless specified otherwise The probing equipment shall be firmly supported The cone and the extension rods must be guided at the beginning of a test to keep the rads straight Pre-boring may be required

The diameter of the bore hale shall be slightly larger than that of the cone The test rig shall be positioned in such a way that the extension rads cannot be bent above the ground surface

43 Driving

The penetrometer shall be continuously driven inta the subsoil The driving rate should be kept between 15 and 30 blows per minute except either when it is already known by borings or has been identified by sound that sands or gravels are being penetrated in this case the driving rate can be increased up to 60 blows per minute Experience has shown that the driving rate in such soils has only a minor influence on the results

All interuptions shall be recorded in the site log All f ac t ors which may influence the penetration resistance (eg tightness of the rod couplings straightness of extension rads) should be checked regularly Any deviations from the recommended test proeectures shall be recorded The rads shall be rotated one and a half turn every meter to keep the hale straight and vertical and to reduce skin frietian (see Section 7 When the depth exceeds 10 m the rads shall be rotated more often eg every 02 m It is recommended to use a mechanized rotating device for large depths

5

The number of blows should be recorded every 01 m for DPL DPM and DPH (N ) andevery 02 m for DPSH (N )

10 (see Section 9 The blows can easily be measured by marking the defined penetration depth (01 or 02 m) on the rads The normal range of blows - especially in view of any quantitative interpretation of the test results shyis between N = 3 and 50 for DPL DPM and DPH and

10 between N

20 = 5 and 100 for DPSH The rebound per blow

should be less than 50 of the penetration per blow In exceptional cases (outside these ranges when the penetration resistance is low eg in soft clays the penetration depth per blow can be recorded In hard soils where the penetration resistance is very high the penetration for a certain number of blows can be recorded

20

It is recommended to measure the torque required for rotating the extension rods to estimate skin friction The skin frietian can also be measured by means of a slip eaupling close to the cone

The precision of measuring the total depth of penetration (tip of the cone) shall be + 002 m

6 PRECAUTIONS CHECKS AND VERIFICATIONS

The free-falling hammer should be raised slowly to ensure that the inertia of the hammer does not carry it above the defined height Also the pickup assembly should be lowered slowly to avoid significant impact on the hammer

The deflection (from a straight line through the ends) at the mid point of a 1-m push rod shall not exceed l mm for the five lowest push rods and 2 mm for the remainder

The tip length of the cone may be cut eg by wear for less than 10 of the diameter of the theoretical tip length of the cone

The maximum deviation of the test rig is 2 i e (horizontal) to 50 (vertical)

Curvature and eccentricity are best measured by eaupling a rod tagether with a straight rod and holding the straight rod in contact with a plane surface

7 SPECIAL FEAIURIS

To eliminate skin friction dri]ling mud can be injected through holes in the hollow rods near the cone The holes have to be directed horizontally or slightly upwards The injection pressure should be sufficient so that the drilling mud fills the annular space between the soil and the rod Alternatively casing can be used

Instead of the hollow extension rods (OD = 22 mm) of the DPL solid rods of OD = 20 mm are being used

8 REPORTING OF RESULTS

The following information shall be reported

a) Location of probing Type of investigation Purpose of probing Date of probing Number of probing

b) Probing number evaluation and location of probing and of the borehole (in case of reference boring) Position of the test rig with respect to the ground surface Elevation or depth of the ground water table

c) Equipment used Type of penetrometer cone rod casing bentonite etc

d) Mass of hammer height of fall and number of blows required per defined penetration

e) Elevation or depth at which the rods were rotated f) Deviations from the normal procedure such as

interruption or damage to rods g) Observations made by the operator such as soil type

sounds in the extension rods indication of stones disturbances etc

An example of a site log is shown in Fig 2

PROJECT lSHEET-NOLOCATION DATE

SECTION JHOL(middot NO OPERATOR ELEVATlONS GROUNO SURfACE GROUNO WAfER TABLE REFH1EhiE UVltL PIJRPOSE CF TEST lTYPE

ECUIPHENT OrNAMI( PROBING ROO CASING POINT DRILLING FlUID CEPTH ampLOW ~ HEGIT NUMampR NOTATIONS REFERENE OF FAl OF ElOS INTERRUPTDNS ROTATION SOJMJS LEVEL m kq m PER 02 m REASON FOR T(RHINATING kOO SHAPE

- - --

--j -- -

- ---- - -

-l -- shy

- --

Fig 2 ExampLe of site Log from dynamic probing

The probing results shall be presented in diagrams which show the N or N values on the harizontal axis and the

10 20 depth on the vertical axis An example is given in Fig 3 If other measurements are taken such as the penetration per blow or the penetration per a certain number of blows these values should be transformed to N N or rd qd values before drawing or

10 20 numbering the diagram Alternatively it may be advantageous to transform the number of blows per defined penetration inta resistance values rd or qd The resistance values shall be plotted on the harizontal axis

If the test was conducted according to the RTP the letter R should appear on site logs graphs etc followed by the abbreviation of the penetrometer type (see Fig 3) All divergences from the RTP must be described completely on logs and graphs containing test results

BLOWS PER O1 m N 10

DPL 10 20

ELEVATION 123 m NAP05 GROUNOWAfER LEV EL o 103 m NAP

E 10 TYPE OF PENETROMETER R DPL~ 15

J PROJEC T- NUMBER zw 7fu 20 DATE OF TEST 88middot03-12 Cl

25 NUMBER OF TEST 13 LOCATION XBOURG

Fig 3 ExampLe of the presentation of the test resuLts from dynamic probing (DPL)

22

9 DKVIATIONS FROM THE REFERENCE TEST

Some light penetrometers have hammers of 20 kg mass (eg Bulgarian State standard 8994-70) in some countries cones with base areas of 5 cm 2 are used (eg Belgium German Standard DIN 4094) In Australia light penetrometers without cones are used during quality controls of compacted sands Some medium penetrometers have hammers of 20 kg mass and heights of fall of 20 cm are being used in some countries (eg DIN 4094 of FRG and Switzerland) Also a height of fall of 50 cm is used in some instances of the DPSH (eg Finland) In France besides the DPSH the DPA of the ISSMFE European Recommended Standard is also used as a reference test (Proc IXth Intern Conf on Soil Mech and Found Eng Vol III p 110 Tokyo 1977) eg the diameter and the shape of the cone are slightly different

In regard to the extension rods of DPSH it is recommended to increase the OD from 32 to 36 mm (this suggestion comes from France Spain and Sweden)

In the case of DPL DPM and DPH the numbers of blows are occasionally counted per 0 2 m depth interval of penetration For DPSH a 03 m depth interval is used occasionally

10 EXPLANATORY NOTES AND COMMENTS

bull Note l

Equations for rd and qd are

M g H r

d A e

M M g H x

M + M A e

where

and qd are resistance values in Pa kPa or MPa

M is the mass of the hammer M is the total mass of the extension rods the

anvi l and the guiding rods H is the height of fall e is the average penetration per blow A is the area at base of the con e g is the acceleration of gravity

r d

rd- and qd-resistances do not relate to strength ranges that the corresponding mechanical device can sustain Especially at high resistances rd- and qd-diagrams should be analysed with caution

23

l

APPENDIX D

INTERNATIONAL REFERENCE TEST PROCEDURE FOR THE WEIGHT SOUNDING TEST

1 SCOPE

The weight-penetrometer consists of a screw-shaped point rads weights and a handle Fig l It is used as a static penetrometer in soft soils when the penetration resistance is less than l kN When the resistance exceeds

kN the penetrometer is rotated and the number of rotations for a given depth of penetration is noted Its ability to penetrate even stiff clays and dense sands is good The penetrometer is primarily used to give a continuous soil profile and an indication of the layer sequence and to determine the lateral extent of different soil layers It is also used to determine whether cohesionless soils are loose medium-dense or dense and to estimate the relative strength of cohesive soils The results obtained in cohesionless soils are also used to get an indication of the bearing capacity of spread faotings and piles

__-re__=- Tap

Handie

Weights 25 kg

~~~EWeights 10 kg -c Ball clamp 5 kg

Piece of wood

Se raper (Rubber)

100m

080m

Rod 16 22 mm

Screw point

Fig l Detaits on the manuatty operated weight penetrometer

2 DEFINITIONs

WST stands for Weight Sounding Test both manually and mechanically operated

WST penetration resistance is either the smallest standard load when the penetrometer sinks without rotation or the number of halfturns per 02 m of penetration when the penetrometer have its maximum load (10 kN) and is rotated

(WST) 3 EQUIPMENT

31 Weights

These comprise one 5 kg clamp two 10 kg weights three 25 kg weights Total 100 kg The weights can be replaced by a dynamometer when the penetrometer is installed manuallyor mechanically inta the soil

32 Rod and eaupling

321 The diameter of the rad should be 19-25 mm preferably 22 mm Regarding material and the influe nce of rad diameter see note l para 11

322 The deviation from the straight axis should not exceed 4deg l ) for the lowest 5 m of the rad and

o 00 8 ) for the remainder Determination of the

00 deviation of the rads see Fig 2 Maximum allowable eccentricity of the eaupling is 01 mm Maximum angular deviation for a joint between two straight rods is 0 005 rad

323 Flush joints should be used

b c ad ~ l 0oo FOR THE 5 LOWER RODS _o_b_

~ 8o FOR THE OTHER RODS

Fig 2 Determination of the deviation from the straight axis of rads

33 Point

331 Manufactured from a 25 mm square steel bar with a total length of 02 m The bar has a 80 mm lang pyramidal tip The point is twisted one turn to the left over a length of 130 mm as shown in Fig 3 If the poin t should be attached to other rod diamete rs than 22 mm as shown in Fig 3 the upper conical part should end with the same diameter as the rod

) These deviations earrespond in case of an even curvature to a deflexion of 1-2 mm in 1 m length respectively

24

332 The diameter of the circumscribed circle of the point shall not exceed 350 ~02 mm for a new point and shall not be less than 320 ~02 mm for a worn point The diameter shall be checked by circular gauges with different inner diameters

Maximum allowable shortening of the length of the point is 15 mm due to wear The tip of the point shall not be bent or broken

34 Additional tools

Two fixed wrenches a handle extraction device and augers for preboring

OIMENSIONS JN mm

x

NEW POINT f 350 02 mm WORN POINT~ 32 0 02 mm

Fig 3 Tolerances for the manufacture of weight penetrometer points applicable to 22 mm rads

4 TESTING PROCEDURE

41 Manual weight sounding)

When the penetrometer is used as a static penetrometer in soft soils the test should be carried out in accordance with clauses 411 and 412 In stiffer soils the penetrometer should be rotated as described in clause 4 l 3

) When manually operated vibrations and sounds from the rod gives a better indication of the soil penetrated Such indications are often lost when the penetrometer is mechanically operated

411 The rod is loaded in steps using the following reference loads

loads in kN mass in kg

o o 005 5

005 + 010 015 5 + lO 15 015 + 010 0 25 15 + lO 25 0 25 + 025 050 25 + 25 50 050 + 025 075 50 + 25 75 075 + 025 100 75 + 25 100

412 The load shall be adjusted to give a rate of penetration of about 50 mmsee This means that the rod must be partly unloaded when a layer of stiff soil such as a dried crust has been penetrated

413 If the penetration resistance exceeds l kN or the penetration rate at l kN is less than 20 mm see the rod should be rotated The load l Y~ is maintained and the number of half turns required to give 02 m of penetration is measured The rod must not be rotated when the penetration resistance is less than l kN

42 Mechanized weight sounding

421 Tests are carried out in a similar manner as for the manual soundings The rod is rotated mechanically in stiff soils

422 The applied load is measured by a dynamometer or a measuring cell attached to the machine

423 When the penetration resistance is less than l kN and rotation is not required the engine must be stopped to prevent the vibrations from the engine to affect the measured penetration resistance The rate of rotation should be between 15 and 40 rpm and should not exceed 50 rpm The average rate of rotation should be 30 rpm (See note 2 para 11)

43 General considerations

431 The possible need to prebare through the upper soil layers shall be estimated in each case (See note 3 para 11)

432 The criteria to be used for the termination of a WST test shall be stated for each investigation eg exceed the minimum penetration resistance or reach a minimum depth (See note 4 para 11)

5 PRECISION OF MEASJRE2oENTS

The maximum allowable deviation of the weights and the dynamometer scale is ~5

The maximum allowable deviation from total penetrated depth is 01 m

25

6 PRECAUTIONS CHECKS AND VERIFICATIONS

Regular checks of the straightness of reds shall be made particularly the lowest five reds cf par 322

Regular inspection shall be made for wear of the point cf 332

WST must not be performed too close to previous soundings or borings normally the distance should be ~ 2 m

7 CALlERATION

Weight pieces should be checked at delivery and marked

Dynamometer should be calibrated at east every 6 months or when any changesservices is made in the apparatus

8 SPECIAL FEAlURES

In order to prevent buckling of the rods when sounding in water the WST ought to be performed in a casing

9 REPORTING OF RESULTS

91 Penetration resistance

9 1 1 When the penetration resistance is less than l kN the reference load required to give a rate of penetration of about 50 mm see shall be recorded against the depth (Fig 4) It should be noted in the boring log and on drawings whether weights or a dynamometer have been used (See note 5 para 11)

912 When the penetration resistance exceeds l kN the number of halfturns required for every 02 m of penetrationshall be recorded (Fig 4)

913 When the penetrometer is driven by blows of a hammer or some of the weights the depths penetrated during driving shall be recorded

92 General notes

921 All observations which may help in the interpretation of the test results shall be noted in the boring log eg diameter of reds sounds and vibrations in the rods when the point penetrates cohesionless soils (stones grave and sand) Also interruptions etc shall be recorded

922 The type of rotating equipment and the rate of rotation shall also be noted in the boring log

93 Presentation of test results

The form of presenting the results of weight sounding tests is shown as an example in Fig 4

E I l shy 5 o

7

WST 22 WEIGHT SOUNOING TEST Z2 mm RODS ht02 m NUMBER OF HALFTURNS PER 02 m

OF PENETRATION DRY CRUST OF CLAY PREBORING TO THIS LEVEL WITH BO mm DIAM AUGER

DIAGRAM TO THE LEFT INDICATE LOADS APPUED IN kN

Fig 4 An example of the presentation of test results from weight sounding test (WST) with 22 mm rods

10 DEVIATIONS FROM THE REFERENCE TEST

All deviations from the Reference Test Procedure shall be described explicitly and completely in the test report

Especially the diameter of the reds ought to be recorded as it can have a major influence on the test results

11 EXPLANATORY NOTES AND COMMENTS

bull Note 1 Clause 321

The reds and couplings should be made of high tensile steel It has to be considered that 25 mm reds may give higher total resistance than 22 mm rods especially in cohesive soils

bull Note 2 Clause 423

Differences between manually and mechanically performed tests sometimes occur Where this may be the case ie when estimating the relative density of loose cohesionless soils camparisens between manually and mechanically performed tests are recommended General ly the measured penetration resistance at rotation is higher for mechanically than for manually operated penetrometers

bull Note 3 Clause 431

In case where the skin frietian resistance along the upper parts of the rod can significantly influence the results a comparison should be made with a test in a prebered hole Preboring is normally required through a dry crust or through a fill When the difference in penetration resistance is arge between the two tests preboring is necessary for all tests within the area The preboring shall be made using an auger with a minimum diameter of 50 mm To estimate the thickness of the dry crust however the sounding test is performed directly from the ground surface

26

bull Note 4 Clause 43 2

A penetration test to firm bottom shall be terminated by striking the rod with a hammer or by dropping s ome of the weight onto the clamp in order to check that the refusal is not temporary If it is possible to penetrate the stiff layer the test shall be continued

Sometimes the weight penetrometer test is followed by percussion boring to deeper levels eg in order to determine the depth to which point-bearing piles need to be driven

bull Note 5 Clause 911

In soft soils when the penetration resistance is less than l kN a dynamometer can be used instead of the weights In this case the recorded load shall be related to the closest reference load and shall be recorded in a similar manner

27

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

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Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

9 DKVIATIONS FROM THE REFERENCE TEST

Some light penetrometers have hammers of 20 kg mass (eg Bulgarian State standard 8994-70) in some countries cones with base areas of 5 cm 2 are used (eg Belgium German Standard DIN 4094) In Australia light penetrometers without cones are used during quality controls of compacted sands Some medium penetrometers have hammers of 20 kg mass and heights of fall of 20 cm are being used in some countries (eg DIN 4094 of FRG and Switzerland) Also a height of fall of 50 cm is used in some instances of the DPSH (eg Finland) In France besides the DPSH the DPA of the ISSMFE European Recommended Standard is also used as a reference test (Proc IXth Intern Conf on Soil Mech and Found Eng Vol III p 110 Tokyo 1977) eg the diameter and the shape of the cone are slightly different

In regard to the extension rods of DPSH it is recommended to increase the OD from 32 to 36 mm (this suggestion comes from France Spain and Sweden)

In the case of DPL DPM and DPH the numbers of blows are occasionally counted per 0 2 m depth interval of penetration For DPSH a 03 m depth interval is used occasionally

10 EXPLANATORY NOTES AND COMMENTS

bull Note l

Equations for rd and qd are

M g H r

d A e

M M g H x

M + M A e

where

and qd are resistance values in Pa kPa or MPa

M is the mass of the hammer M is the total mass of the extension rods the

anvi l and the guiding rods H is the height of fall e is the average penetration per blow A is the area at base of the con e g is the acceleration of gravity

r d

rd- and qd-resistances do not relate to strength ranges that the corresponding mechanical device can sustain Especially at high resistances rd- and qd-diagrams should be analysed with caution

23

l

APPENDIX D

INTERNATIONAL REFERENCE TEST PROCEDURE FOR THE WEIGHT SOUNDING TEST

1 SCOPE

The weight-penetrometer consists of a screw-shaped point rads weights and a handle Fig l It is used as a static penetrometer in soft soils when the penetration resistance is less than l kN When the resistance exceeds

kN the penetrometer is rotated and the number of rotations for a given depth of penetration is noted Its ability to penetrate even stiff clays and dense sands is good The penetrometer is primarily used to give a continuous soil profile and an indication of the layer sequence and to determine the lateral extent of different soil layers It is also used to determine whether cohesionless soils are loose medium-dense or dense and to estimate the relative strength of cohesive soils The results obtained in cohesionless soils are also used to get an indication of the bearing capacity of spread faotings and piles

__-re__=- Tap

Handie

Weights 25 kg

~~~EWeights 10 kg -c Ball clamp 5 kg

Piece of wood

Se raper (Rubber)

100m

080m

Rod 16 22 mm

Screw point

Fig l Detaits on the manuatty operated weight penetrometer

2 DEFINITIONs

WST stands for Weight Sounding Test both manually and mechanically operated

WST penetration resistance is either the smallest standard load when the penetrometer sinks without rotation or the number of halfturns per 02 m of penetration when the penetrometer have its maximum load (10 kN) and is rotated

(WST) 3 EQUIPMENT

31 Weights

These comprise one 5 kg clamp two 10 kg weights three 25 kg weights Total 100 kg The weights can be replaced by a dynamometer when the penetrometer is installed manuallyor mechanically inta the soil

32 Rod and eaupling

321 The diameter of the rad should be 19-25 mm preferably 22 mm Regarding material and the influe nce of rad diameter see note l para 11

322 The deviation from the straight axis should not exceed 4deg l ) for the lowest 5 m of the rad and

o 00 8 ) for the remainder Determination of the

00 deviation of the rads see Fig 2 Maximum allowable eccentricity of the eaupling is 01 mm Maximum angular deviation for a joint between two straight rods is 0 005 rad

323 Flush joints should be used

b c ad ~ l 0oo FOR THE 5 LOWER RODS _o_b_

~ 8o FOR THE OTHER RODS

Fig 2 Determination of the deviation from the straight axis of rads

33 Point

331 Manufactured from a 25 mm square steel bar with a total length of 02 m The bar has a 80 mm lang pyramidal tip The point is twisted one turn to the left over a length of 130 mm as shown in Fig 3 If the poin t should be attached to other rod diamete rs than 22 mm as shown in Fig 3 the upper conical part should end with the same diameter as the rod

) These deviations earrespond in case of an even curvature to a deflexion of 1-2 mm in 1 m length respectively

24

332 The diameter of the circumscribed circle of the point shall not exceed 350 ~02 mm for a new point and shall not be less than 320 ~02 mm for a worn point The diameter shall be checked by circular gauges with different inner diameters

Maximum allowable shortening of the length of the point is 15 mm due to wear The tip of the point shall not be bent or broken

34 Additional tools

Two fixed wrenches a handle extraction device and augers for preboring

OIMENSIONS JN mm

x

NEW POINT f 350 02 mm WORN POINT~ 32 0 02 mm

Fig 3 Tolerances for the manufacture of weight penetrometer points applicable to 22 mm rads

4 TESTING PROCEDURE

41 Manual weight sounding)

When the penetrometer is used as a static penetrometer in soft soils the test should be carried out in accordance with clauses 411 and 412 In stiffer soils the penetrometer should be rotated as described in clause 4 l 3

) When manually operated vibrations and sounds from the rod gives a better indication of the soil penetrated Such indications are often lost when the penetrometer is mechanically operated

411 The rod is loaded in steps using the following reference loads

loads in kN mass in kg

o o 005 5

005 + 010 015 5 + lO 15 015 + 010 0 25 15 + lO 25 0 25 + 025 050 25 + 25 50 050 + 025 075 50 + 25 75 075 + 025 100 75 + 25 100

412 The load shall be adjusted to give a rate of penetration of about 50 mmsee This means that the rod must be partly unloaded when a layer of stiff soil such as a dried crust has been penetrated

413 If the penetration resistance exceeds l kN or the penetration rate at l kN is less than 20 mm see the rod should be rotated The load l Y~ is maintained and the number of half turns required to give 02 m of penetration is measured The rod must not be rotated when the penetration resistance is less than l kN

42 Mechanized weight sounding

421 Tests are carried out in a similar manner as for the manual soundings The rod is rotated mechanically in stiff soils

422 The applied load is measured by a dynamometer or a measuring cell attached to the machine

423 When the penetration resistance is less than l kN and rotation is not required the engine must be stopped to prevent the vibrations from the engine to affect the measured penetration resistance The rate of rotation should be between 15 and 40 rpm and should not exceed 50 rpm The average rate of rotation should be 30 rpm (See note 2 para 11)

43 General considerations

431 The possible need to prebare through the upper soil layers shall be estimated in each case (See note 3 para 11)

432 The criteria to be used for the termination of a WST test shall be stated for each investigation eg exceed the minimum penetration resistance or reach a minimum depth (See note 4 para 11)

5 PRECISION OF MEASJRE2oENTS

The maximum allowable deviation of the weights and the dynamometer scale is ~5

The maximum allowable deviation from total penetrated depth is 01 m

25

6 PRECAUTIONS CHECKS AND VERIFICATIONS

Regular checks of the straightness of reds shall be made particularly the lowest five reds cf par 322

Regular inspection shall be made for wear of the point cf 332

WST must not be performed too close to previous soundings or borings normally the distance should be ~ 2 m

7 CALlERATION

Weight pieces should be checked at delivery and marked

Dynamometer should be calibrated at east every 6 months or when any changesservices is made in the apparatus

8 SPECIAL FEAlURES

In order to prevent buckling of the rods when sounding in water the WST ought to be performed in a casing

9 REPORTING OF RESULTS

91 Penetration resistance

9 1 1 When the penetration resistance is less than l kN the reference load required to give a rate of penetration of about 50 mm see shall be recorded against the depth (Fig 4) It should be noted in the boring log and on drawings whether weights or a dynamometer have been used (See note 5 para 11)

912 When the penetration resistance exceeds l kN the number of halfturns required for every 02 m of penetrationshall be recorded (Fig 4)

913 When the penetrometer is driven by blows of a hammer or some of the weights the depths penetrated during driving shall be recorded

92 General notes

921 All observations which may help in the interpretation of the test results shall be noted in the boring log eg diameter of reds sounds and vibrations in the rods when the point penetrates cohesionless soils (stones grave and sand) Also interruptions etc shall be recorded

922 The type of rotating equipment and the rate of rotation shall also be noted in the boring log

93 Presentation of test results

The form of presenting the results of weight sounding tests is shown as an example in Fig 4

E I l shy 5 o

7

WST 22 WEIGHT SOUNOING TEST Z2 mm RODS ht02 m NUMBER OF HALFTURNS PER 02 m

OF PENETRATION DRY CRUST OF CLAY PREBORING TO THIS LEVEL WITH BO mm DIAM AUGER

DIAGRAM TO THE LEFT INDICATE LOADS APPUED IN kN

Fig 4 An example of the presentation of test results from weight sounding test (WST) with 22 mm rods

10 DEVIATIONS FROM THE REFERENCE TEST

All deviations from the Reference Test Procedure shall be described explicitly and completely in the test report

Especially the diameter of the reds ought to be recorded as it can have a major influence on the test results

11 EXPLANATORY NOTES AND COMMENTS

bull Note 1 Clause 321

The reds and couplings should be made of high tensile steel It has to be considered that 25 mm reds may give higher total resistance than 22 mm rods especially in cohesive soils

bull Note 2 Clause 423

Differences between manually and mechanically performed tests sometimes occur Where this may be the case ie when estimating the relative density of loose cohesionless soils camparisens between manually and mechanically performed tests are recommended General ly the measured penetration resistance at rotation is higher for mechanically than for manually operated penetrometers

bull Note 3 Clause 431

In case where the skin frietian resistance along the upper parts of the rod can significantly influence the results a comparison should be made with a test in a prebered hole Preboring is normally required through a dry crust or through a fill When the difference in penetration resistance is arge between the two tests preboring is necessary for all tests within the area The preboring shall be made using an auger with a minimum diameter of 50 mm To estimate the thickness of the dry crust however the sounding test is performed directly from the ground surface

26

bull Note 4 Clause 43 2

A penetration test to firm bottom shall be terminated by striking the rod with a hammer or by dropping s ome of the weight onto the clamp in order to check that the refusal is not temporary If it is possible to penetrate the stiff layer the test shall be continued

Sometimes the weight penetrometer test is followed by percussion boring to deeper levels eg in order to determine the depth to which point-bearing piles need to be driven

bull Note 5 Clause 911

In soft soils when the penetration resistance is less than l kN a dynamometer can be used instead of the weights In this case the recorded load shall be related to the closest reference load and shall be recorded in a similar manner

27

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

joalzomi tre

ett

-- shy

- 00001

--L-cOOc08

MPa

HPa

0 7

1 O

HPa

HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

l

APPENDIX D

INTERNATIONAL REFERENCE TEST PROCEDURE FOR THE WEIGHT SOUNDING TEST

1 SCOPE

The weight-penetrometer consists of a screw-shaped point rads weights and a handle Fig l It is used as a static penetrometer in soft soils when the penetration resistance is less than l kN When the resistance exceeds

kN the penetrometer is rotated and the number of rotations for a given depth of penetration is noted Its ability to penetrate even stiff clays and dense sands is good The penetrometer is primarily used to give a continuous soil profile and an indication of the layer sequence and to determine the lateral extent of different soil layers It is also used to determine whether cohesionless soils are loose medium-dense or dense and to estimate the relative strength of cohesive soils The results obtained in cohesionless soils are also used to get an indication of the bearing capacity of spread faotings and piles

__-re__=- Tap

Handie

Weights 25 kg

~~~EWeights 10 kg -c Ball clamp 5 kg

Piece of wood

Se raper (Rubber)

100m

080m

Rod 16 22 mm

Screw point

Fig l Detaits on the manuatty operated weight penetrometer

2 DEFINITIONs

WST stands for Weight Sounding Test both manually and mechanically operated

WST penetration resistance is either the smallest standard load when the penetrometer sinks without rotation or the number of halfturns per 02 m of penetration when the penetrometer have its maximum load (10 kN) and is rotated

(WST) 3 EQUIPMENT

31 Weights

These comprise one 5 kg clamp two 10 kg weights three 25 kg weights Total 100 kg The weights can be replaced by a dynamometer when the penetrometer is installed manuallyor mechanically inta the soil

32 Rod and eaupling

321 The diameter of the rad should be 19-25 mm preferably 22 mm Regarding material and the influe nce of rad diameter see note l para 11

322 The deviation from the straight axis should not exceed 4deg l ) for the lowest 5 m of the rad and

o 00 8 ) for the remainder Determination of the

00 deviation of the rads see Fig 2 Maximum allowable eccentricity of the eaupling is 01 mm Maximum angular deviation for a joint between two straight rods is 0 005 rad

323 Flush joints should be used

b c ad ~ l 0oo FOR THE 5 LOWER RODS _o_b_

~ 8o FOR THE OTHER RODS

Fig 2 Determination of the deviation from the straight axis of rads

33 Point

331 Manufactured from a 25 mm square steel bar with a total length of 02 m The bar has a 80 mm lang pyramidal tip The point is twisted one turn to the left over a length of 130 mm as shown in Fig 3 If the poin t should be attached to other rod diamete rs than 22 mm as shown in Fig 3 the upper conical part should end with the same diameter as the rod

) These deviations earrespond in case of an even curvature to a deflexion of 1-2 mm in 1 m length respectively

24

332 The diameter of the circumscribed circle of the point shall not exceed 350 ~02 mm for a new point and shall not be less than 320 ~02 mm for a worn point The diameter shall be checked by circular gauges with different inner diameters

Maximum allowable shortening of the length of the point is 15 mm due to wear The tip of the point shall not be bent or broken

34 Additional tools

Two fixed wrenches a handle extraction device and augers for preboring

OIMENSIONS JN mm

x

NEW POINT f 350 02 mm WORN POINT~ 32 0 02 mm

Fig 3 Tolerances for the manufacture of weight penetrometer points applicable to 22 mm rads

4 TESTING PROCEDURE

41 Manual weight sounding)

When the penetrometer is used as a static penetrometer in soft soils the test should be carried out in accordance with clauses 411 and 412 In stiffer soils the penetrometer should be rotated as described in clause 4 l 3

) When manually operated vibrations and sounds from the rod gives a better indication of the soil penetrated Such indications are often lost when the penetrometer is mechanically operated

411 The rod is loaded in steps using the following reference loads

loads in kN mass in kg

o o 005 5

005 + 010 015 5 + lO 15 015 + 010 0 25 15 + lO 25 0 25 + 025 050 25 + 25 50 050 + 025 075 50 + 25 75 075 + 025 100 75 + 25 100

412 The load shall be adjusted to give a rate of penetration of about 50 mmsee This means that the rod must be partly unloaded when a layer of stiff soil such as a dried crust has been penetrated

413 If the penetration resistance exceeds l kN or the penetration rate at l kN is less than 20 mm see the rod should be rotated The load l Y~ is maintained and the number of half turns required to give 02 m of penetration is measured The rod must not be rotated when the penetration resistance is less than l kN

42 Mechanized weight sounding

421 Tests are carried out in a similar manner as for the manual soundings The rod is rotated mechanically in stiff soils

422 The applied load is measured by a dynamometer or a measuring cell attached to the machine

423 When the penetration resistance is less than l kN and rotation is not required the engine must be stopped to prevent the vibrations from the engine to affect the measured penetration resistance The rate of rotation should be between 15 and 40 rpm and should not exceed 50 rpm The average rate of rotation should be 30 rpm (See note 2 para 11)

43 General considerations

431 The possible need to prebare through the upper soil layers shall be estimated in each case (See note 3 para 11)

432 The criteria to be used for the termination of a WST test shall be stated for each investigation eg exceed the minimum penetration resistance or reach a minimum depth (See note 4 para 11)

5 PRECISION OF MEASJRE2oENTS

The maximum allowable deviation of the weights and the dynamometer scale is ~5

The maximum allowable deviation from total penetrated depth is 01 m

25

6 PRECAUTIONS CHECKS AND VERIFICATIONS

Regular checks of the straightness of reds shall be made particularly the lowest five reds cf par 322

Regular inspection shall be made for wear of the point cf 332

WST must not be performed too close to previous soundings or borings normally the distance should be ~ 2 m

7 CALlERATION

Weight pieces should be checked at delivery and marked

Dynamometer should be calibrated at east every 6 months or when any changesservices is made in the apparatus

8 SPECIAL FEAlURES

In order to prevent buckling of the rods when sounding in water the WST ought to be performed in a casing

9 REPORTING OF RESULTS

91 Penetration resistance

9 1 1 When the penetration resistance is less than l kN the reference load required to give a rate of penetration of about 50 mm see shall be recorded against the depth (Fig 4) It should be noted in the boring log and on drawings whether weights or a dynamometer have been used (See note 5 para 11)

912 When the penetration resistance exceeds l kN the number of halfturns required for every 02 m of penetrationshall be recorded (Fig 4)

913 When the penetrometer is driven by blows of a hammer or some of the weights the depths penetrated during driving shall be recorded

92 General notes

921 All observations which may help in the interpretation of the test results shall be noted in the boring log eg diameter of reds sounds and vibrations in the rods when the point penetrates cohesionless soils (stones grave and sand) Also interruptions etc shall be recorded

922 The type of rotating equipment and the rate of rotation shall also be noted in the boring log

93 Presentation of test results

The form of presenting the results of weight sounding tests is shown as an example in Fig 4

E I l shy 5 o

7

WST 22 WEIGHT SOUNOING TEST Z2 mm RODS ht02 m NUMBER OF HALFTURNS PER 02 m

OF PENETRATION DRY CRUST OF CLAY PREBORING TO THIS LEVEL WITH BO mm DIAM AUGER

DIAGRAM TO THE LEFT INDICATE LOADS APPUED IN kN

Fig 4 An example of the presentation of test results from weight sounding test (WST) with 22 mm rods

10 DEVIATIONS FROM THE REFERENCE TEST

All deviations from the Reference Test Procedure shall be described explicitly and completely in the test report

Especially the diameter of the reds ought to be recorded as it can have a major influence on the test results

11 EXPLANATORY NOTES AND COMMENTS

bull Note 1 Clause 321

The reds and couplings should be made of high tensile steel It has to be considered that 25 mm reds may give higher total resistance than 22 mm rods especially in cohesive soils

bull Note 2 Clause 423

Differences between manually and mechanically performed tests sometimes occur Where this may be the case ie when estimating the relative density of loose cohesionless soils camparisens between manually and mechanically performed tests are recommended General ly the measured penetration resistance at rotation is higher for mechanically than for manually operated penetrometers

bull Note 3 Clause 431

In case where the skin frietian resistance along the upper parts of the rod can significantly influence the results a comparison should be made with a test in a prebered hole Preboring is normally required through a dry crust or through a fill When the difference in penetration resistance is arge between the two tests preboring is necessary for all tests within the area The preboring shall be made using an auger with a minimum diameter of 50 mm To estimate the thickness of the dry crust however the sounding test is performed directly from the ground surface

26

bull Note 4 Clause 43 2

A penetration test to firm bottom shall be terminated by striking the rod with a hammer or by dropping s ome of the weight onto the clamp in order to check that the refusal is not temporary If it is possible to penetrate the stiff layer the test shall be continued

Sometimes the weight penetrometer test is followed by percussion boring to deeper levels eg in order to determine the depth to which point-bearing piles need to be driven

bull Note 5 Clause 911

In soft soils when the penetration resistance is less than l kN a dynamometer can be used instead of the weights In this case the recorded load shall be related to the closest reference load and shall be recorded in a similar manner

27

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

joalzomi tre

ett

-- shy

- 00001

--L-cOOc08

MPa

HPa

0 7

1 O

HPa

HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

332 The diameter of the circumscribed circle of the point shall not exceed 350 ~02 mm for a new point and shall not be less than 320 ~02 mm for a worn point The diameter shall be checked by circular gauges with different inner diameters

Maximum allowable shortening of the length of the point is 15 mm due to wear The tip of the point shall not be bent or broken

34 Additional tools

Two fixed wrenches a handle extraction device and augers for preboring

OIMENSIONS JN mm

x

NEW POINT f 350 02 mm WORN POINT~ 32 0 02 mm

Fig 3 Tolerances for the manufacture of weight penetrometer points applicable to 22 mm rads

4 TESTING PROCEDURE

41 Manual weight sounding)

When the penetrometer is used as a static penetrometer in soft soils the test should be carried out in accordance with clauses 411 and 412 In stiffer soils the penetrometer should be rotated as described in clause 4 l 3

) When manually operated vibrations and sounds from the rod gives a better indication of the soil penetrated Such indications are often lost when the penetrometer is mechanically operated

411 The rod is loaded in steps using the following reference loads

loads in kN mass in kg

o o 005 5

005 + 010 015 5 + lO 15 015 + 010 0 25 15 + lO 25 0 25 + 025 050 25 + 25 50 050 + 025 075 50 + 25 75 075 + 025 100 75 + 25 100

412 The load shall be adjusted to give a rate of penetration of about 50 mmsee This means that the rod must be partly unloaded when a layer of stiff soil such as a dried crust has been penetrated

413 If the penetration resistance exceeds l kN or the penetration rate at l kN is less than 20 mm see the rod should be rotated The load l Y~ is maintained and the number of half turns required to give 02 m of penetration is measured The rod must not be rotated when the penetration resistance is less than l kN

42 Mechanized weight sounding

421 Tests are carried out in a similar manner as for the manual soundings The rod is rotated mechanically in stiff soils

422 The applied load is measured by a dynamometer or a measuring cell attached to the machine

423 When the penetration resistance is less than l kN and rotation is not required the engine must be stopped to prevent the vibrations from the engine to affect the measured penetration resistance The rate of rotation should be between 15 and 40 rpm and should not exceed 50 rpm The average rate of rotation should be 30 rpm (See note 2 para 11)

43 General considerations

431 The possible need to prebare through the upper soil layers shall be estimated in each case (See note 3 para 11)

432 The criteria to be used for the termination of a WST test shall be stated for each investigation eg exceed the minimum penetration resistance or reach a minimum depth (See note 4 para 11)

5 PRECISION OF MEASJRE2oENTS

The maximum allowable deviation of the weights and the dynamometer scale is ~5

The maximum allowable deviation from total penetrated depth is 01 m

25

6 PRECAUTIONS CHECKS AND VERIFICATIONS

Regular checks of the straightness of reds shall be made particularly the lowest five reds cf par 322

Regular inspection shall be made for wear of the point cf 332

WST must not be performed too close to previous soundings or borings normally the distance should be ~ 2 m

7 CALlERATION

Weight pieces should be checked at delivery and marked

Dynamometer should be calibrated at east every 6 months or when any changesservices is made in the apparatus

8 SPECIAL FEAlURES

In order to prevent buckling of the rods when sounding in water the WST ought to be performed in a casing

9 REPORTING OF RESULTS

91 Penetration resistance

9 1 1 When the penetration resistance is less than l kN the reference load required to give a rate of penetration of about 50 mm see shall be recorded against the depth (Fig 4) It should be noted in the boring log and on drawings whether weights or a dynamometer have been used (See note 5 para 11)

912 When the penetration resistance exceeds l kN the number of halfturns required for every 02 m of penetrationshall be recorded (Fig 4)

913 When the penetrometer is driven by blows of a hammer or some of the weights the depths penetrated during driving shall be recorded

92 General notes

921 All observations which may help in the interpretation of the test results shall be noted in the boring log eg diameter of reds sounds and vibrations in the rods when the point penetrates cohesionless soils (stones grave and sand) Also interruptions etc shall be recorded

922 The type of rotating equipment and the rate of rotation shall also be noted in the boring log

93 Presentation of test results

The form of presenting the results of weight sounding tests is shown as an example in Fig 4

E I l shy 5 o

7

WST 22 WEIGHT SOUNOING TEST Z2 mm RODS ht02 m NUMBER OF HALFTURNS PER 02 m

OF PENETRATION DRY CRUST OF CLAY PREBORING TO THIS LEVEL WITH BO mm DIAM AUGER

DIAGRAM TO THE LEFT INDICATE LOADS APPUED IN kN

Fig 4 An example of the presentation of test results from weight sounding test (WST) with 22 mm rods

10 DEVIATIONS FROM THE REFERENCE TEST

All deviations from the Reference Test Procedure shall be described explicitly and completely in the test report

Especially the diameter of the reds ought to be recorded as it can have a major influence on the test results

11 EXPLANATORY NOTES AND COMMENTS

bull Note 1 Clause 321

The reds and couplings should be made of high tensile steel It has to be considered that 25 mm reds may give higher total resistance than 22 mm rods especially in cohesive soils

bull Note 2 Clause 423

Differences between manually and mechanically performed tests sometimes occur Where this may be the case ie when estimating the relative density of loose cohesionless soils camparisens between manually and mechanically performed tests are recommended General ly the measured penetration resistance at rotation is higher for mechanically than for manually operated penetrometers

bull Note 3 Clause 431

In case where the skin frietian resistance along the upper parts of the rod can significantly influence the results a comparison should be made with a test in a prebered hole Preboring is normally required through a dry crust or through a fill When the difference in penetration resistance is arge between the two tests preboring is necessary for all tests within the area The preboring shall be made using an auger with a minimum diameter of 50 mm To estimate the thickness of the dry crust however the sounding test is performed directly from the ground surface

26

bull Note 4 Clause 43 2

A penetration test to firm bottom shall be terminated by striking the rod with a hammer or by dropping s ome of the weight onto the clamp in order to check that the refusal is not temporary If it is possible to penetrate the stiff layer the test shall be continued

Sometimes the weight penetrometer test is followed by percussion boring to deeper levels eg in order to determine the depth to which point-bearing piles need to be driven

bull Note 5 Clause 911

In soft soils when the penetration resistance is less than l kN a dynamometer can be used instead of the weights In this case the recorded load shall be related to the closest reference load and shall be recorded in a similar manner

27

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

joalzomi tre

ett

-- shy

- 00001

--L-cOOc08

MPa

HPa

0 7

1 O

HPa

HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

6 PRECAUTIONS CHECKS AND VERIFICATIONS

Regular checks of the straightness of reds shall be made particularly the lowest five reds cf par 322

Regular inspection shall be made for wear of the point cf 332

WST must not be performed too close to previous soundings or borings normally the distance should be ~ 2 m

7 CALlERATION

Weight pieces should be checked at delivery and marked

Dynamometer should be calibrated at east every 6 months or when any changesservices is made in the apparatus

8 SPECIAL FEAlURES

In order to prevent buckling of the rods when sounding in water the WST ought to be performed in a casing

9 REPORTING OF RESULTS

91 Penetration resistance

9 1 1 When the penetration resistance is less than l kN the reference load required to give a rate of penetration of about 50 mm see shall be recorded against the depth (Fig 4) It should be noted in the boring log and on drawings whether weights or a dynamometer have been used (See note 5 para 11)

912 When the penetration resistance exceeds l kN the number of halfturns required for every 02 m of penetrationshall be recorded (Fig 4)

913 When the penetrometer is driven by blows of a hammer or some of the weights the depths penetrated during driving shall be recorded

92 General notes

921 All observations which may help in the interpretation of the test results shall be noted in the boring log eg diameter of reds sounds and vibrations in the rods when the point penetrates cohesionless soils (stones grave and sand) Also interruptions etc shall be recorded

922 The type of rotating equipment and the rate of rotation shall also be noted in the boring log

93 Presentation of test results

The form of presenting the results of weight sounding tests is shown as an example in Fig 4

E I l shy 5 o

7

WST 22 WEIGHT SOUNOING TEST Z2 mm RODS ht02 m NUMBER OF HALFTURNS PER 02 m

OF PENETRATION DRY CRUST OF CLAY PREBORING TO THIS LEVEL WITH BO mm DIAM AUGER

DIAGRAM TO THE LEFT INDICATE LOADS APPUED IN kN

Fig 4 An example of the presentation of test results from weight sounding test (WST) with 22 mm rods

10 DEVIATIONS FROM THE REFERENCE TEST

All deviations from the Reference Test Procedure shall be described explicitly and completely in the test report

Especially the diameter of the reds ought to be recorded as it can have a major influence on the test results

11 EXPLANATORY NOTES AND COMMENTS

bull Note 1 Clause 321

The reds and couplings should be made of high tensile steel It has to be considered that 25 mm reds may give higher total resistance than 22 mm rods especially in cohesive soils

bull Note 2 Clause 423

Differences between manually and mechanically performed tests sometimes occur Where this may be the case ie when estimating the relative density of loose cohesionless soils camparisens between manually and mechanically performed tests are recommended General ly the measured penetration resistance at rotation is higher for mechanically than for manually operated penetrometers

bull Note 3 Clause 431

In case where the skin frietian resistance along the upper parts of the rod can significantly influence the results a comparison should be made with a test in a prebered hole Preboring is normally required through a dry crust or through a fill When the difference in penetration resistance is arge between the two tests preboring is necessary for all tests within the area The preboring shall be made using an auger with a minimum diameter of 50 mm To estimate the thickness of the dry crust however the sounding test is performed directly from the ground surface

26

bull Note 4 Clause 43 2

A penetration test to firm bottom shall be terminated by striking the rod with a hammer or by dropping s ome of the weight onto the clamp in order to check that the refusal is not temporary If it is possible to penetrate the stiff layer the test shall be continued

Sometimes the weight penetrometer test is followed by percussion boring to deeper levels eg in order to determine the depth to which point-bearing piles need to be driven

bull Note 5 Clause 911

In soft soils when the penetration resistance is less than l kN a dynamometer can be used instead of the weights In this case the recorded load shall be related to the closest reference load and shall be recorded in a similar manner

27

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

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INTERSTITIELLE 0 2 0 4 0 6

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Q lt(

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0 lt( Q

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-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

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DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

bull Note 4 Clause 43 2

A penetration test to firm bottom shall be terminated by striking the rod with a hammer or by dropping s ome of the weight onto the clamp in order to check that the refusal is not temporary If it is possible to penetrate the stiff layer the test shall be continued

Sometimes the weight penetrometer test is followed by percussion boring to deeper levels eg in order to determine the depth to which point-bearing piles need to be driven

bull Note 5 Clause 911

In soft soils when the penetration resistance is less than l kN a dynamometer can be used instead of the weights In this case the recorded load shall be related to the closest reference load and shall be recorded in a similar manner

27

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

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RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

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DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

APPENDICE A

MODE OPERATOIRE DE LESSAI DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION AU CONE (CPT)

l OBJET

Lessai de penetration au coumlne consiste aring veriner dans le sol aring une vitesse suffisamment faible un train de tubes termine aring sa partie inferieure par une coumlne et aring mesurer de maniere continue ou aring intervalles de profondeur determines la resistance au coumlne et si desire leffort total denfoncement etou leffort de frottement sur un manchon de frottement En plus la pression deau interstitielle existant aring linterface entre la pointe du penetrometre et le sol peut etre mesuree pendant la penetration au moyen dun capteur de pression dans le coumlne Cette pression deau interstitielle camprend laugmentation ou la diminution de la pression deau intersititelle due aring la compression ou a la dilatance du sol sature situe autour du coumlne resultant de la penetration du coumlne et des tubes de fon~age dans le sol

On execute les essais de penetration au coumlne afin dobtenir des donnees relatives aring un ou plusieurs des points suivants

l la stratigraphie des couches du site et leur homogeneite

2 la profondeur des couches dures la localisation des cavites vides et autres discontinuites

3 lidentification des sols 4 les caracteristiques physiques et mecaniques des sols 5 le battage et la capacite portante des pieux

2 DEFINITION

21 Essai de penetration au coumlne (en abrege CPT dapres lexpression anglaise) ce terme couvre ce qui etait appele Essai de penetration statique ou Essai de penetration quasi-statique ou Essai de penetration hollandais

22 Penetrometre appareil qui consiste en un train de tubes cylindriques termine par un embout appele pointe du penetrometre et les dispositifs de mesure pour la determination de leffort sur le coumlne et une ou plusieurs des caracteristiques suivantes leffort de frottement lateral local leffort total la pression deau interstitielle existant dans le voisinage immediat du coumlne pendant la penetration

23 Pointe embout dune longueur de 1000 mm aring lextremite du train de tubes qui camprend les elements actifs de de shytermination de leffort sur le coumlne leffort de fretteshyment lateral local et la pression deau interstitielle existant aring linterface entre le coumlne (definition voir seetian 32) et le sol pendant la penetration

231 FOt la partie cylindrique de lembout au-dessus du coumlne etou du manchon de frottement

2 4 Coumlne la piece terminale de la pointe penetrometrique sur laquelle leffort de pointe est mesure

241 Suivant le degre de liberte du coumlne on distingue

- les paintes aring coumlne fixe ou le coumlne ne peut subir que des micro-deplacements par rapport aux autres elements de la pointe - les paintes aring coumlne mobile ou le coumlne peut se deplacer librement par rapport aux autres elements de la pointe

242 Suivant la forme du coumlne on distingue

- le coumlne simple dans lequel la longueur de la partie cylindrique prolongeant la partie conique est notablement plus petite que le diametre du coumlne - le coumlne aring jupe dans lequel la partie conique est prolongee par un manchon plus ou moins cylindrique dont le diametre est plus petit que le diametre du coumlne et dont la longueur est de l aring 3 fois le diametre du coumlne ce manchon est appele la jupe

243 Piezocoumlne un coumlne comportant un filtre situe dans la partie conique ou dans la prolongation cylindrique (defintion voir section 32) pour mesurer la pression deau interstitielle existant dans le sol pendant la penetration au moyen dun capteur de pression

25 Manchon de frottement partie de la pointe penetrometrique sur laquelle on mesure le frottement lateral l ocal

26 Systeme de aesure le systeme camprend les dispositifs de mesure eux-memes et les mayens de transmission de information depuis la pointe jusquaring un endroit ou elle peut etre lue ou enregistree On peut definir par exemple

261 Les penetrometres electriques qui utilisent un appareillage electrique tel que jauges de contrainte cordes vibrantes etc inclus dans la pointe

262 Les penetrometres mecaniques qui utilisent un train de tiges interieures pour transmettre leffort au coumlne

263 Les penetrometres hydrauliques et pneumatiques qui utilisent des appareillages hydrauliques ou pneumatiques inclus dans la pointe

27 Tubes de fon~age tubes de forte epaisseur ou tiges de preference dune longueur de l m utilises pour foncer la pointe penetrometrique

28 Tiges interieures tiges pleines eaulissant dans les tubes de fon~age qui prolongent la pointe dun penetrometre mecanique

29 Appareil de fon~age materiel qui fonce le penetrometre dans le sol La reaction necessaire est obtenue aring laide dun poids mortet ou dancrages

28

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

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HPa

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HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

210 Dispositif de reduction du frotteaent petite protuberance leeale sur le tube de fon~age placee aushydessus de la pointe penetrometrique et destinee aring reduire le frottement sur le tube de fon~age

211 Essais de penetration continue et discontinue (voir note 1)

2111 Essai de penetration continue essai de penetration dans lequel tous les elements de la pointe senfoncent aring

la meme vitesse durant la mesure de resistance de coumlne

2112 Essai de penetration discontinue essai de penetration dans lequel seul le coumlne senfonce durant la mesure de la resistance aring lenfoncement les autres elements de la pointe restant stationnaires Quand le penetrometre comporte un manchon de frottement la mesure de la somme des resistances de coumlne et de manchon est obtenue par lenfoncement simultane du coumlne et du manchon les autres elements de la pointe restant stationnaires

2 12 Resistance au coumlne qc la resistance au coumlne qc est obtenue en divisant leffort total sur le coumlne Qc par la surface de la base du coumlne Ac

A c

Cette resistance est exprimee en MPa ou en kPa

213 Frottement lateral local unitaire f le s frottement lateral local unitaire f est obtenu en

s divisant la force totale de frottement Qs qui agit sur le manchon de frottement par sa surface laterale A s

f A s s

Le frottement lateral local unitaire fs est exprime en Pa kPa ou MPa

214 Effort total denfoncement Qt force totale necessaire pour enfoncer ensemble tube-coumlne dans le sol Qt est exprime en kN

215 Effort total de frottement lateral Qst il est generalement obtenu par difference entre leffort total denfoncement Qt et leffort total sur le coumlne

Qc

Qst est exprime en kN comme Qt et Qc

Certains penetrometres permettent la mesure directe de

Qst

216 Pourcentage de frottement Rf et indice de frottement If (voir note 2)

2161 Pourcentage de frottement Rf rapport du frottement lateral local unitaire fs aring la resistance au coumlne qc mesures aring la meme profondeur et exprime en pour-cents

2162 Indice de frott~nt If rapport de la resistance au coumlne qc au frottement lateral local unitaire f mesures aring la meme profondeur

s

3 PENIITROMETRE ET EQUIPEJmNT POUR L ISSAI DE REFERENCE

31 Geometrie generale de la pointe dans lessai de penetration de reference des paintes avec ou sans manchon de frottement et avec ou sans capteur de pression deau peuvent etre utilisees Sil existe un vide entre le coumlne et les autres elements de la pointe il doit etre limite au minimum necessaire au fonetiennement des organes de mesure et con~u et realise de maniere aring prevenir et empecher lentree de particules de sol (voir note 3) Ceci sapplique egalement aux vides entre chacune des extremites du manchon de frottement et les autres elements de la pointe La pointe le manchon de frottement sil existe et le corps de la pointe doivent etre parfaitement concentriques

Le diametre du fut de la pointe penetrometrique ne peut nulle part etre inferieur de plus de 03 mm ni superieur de plus de l mm au diametre nominal de 357 mm du coumlne de reference

De plus dans le cas dune pointe avec manchon de frottement aucune partie de la pointe penetrometrique ne peut etre saillante par rapport au manchon de frottement

Un exemple de penetrometre de reference est donne a la fig 1(a) et l(b)

fut d e ta pointe pemitroshymetrique

r

e T A J

a middot ( se roppor t e o u n Cgt

eot e d e lo s eetia n o

tran sversale ) menehon d e

( c l frottement

r~ ~ ful de lo l ~ V po1nte pene-

E l --J tromftnque ~ - ~ joint detoneh eite

E4 -j( ~ 1ornt d etaneherte g tl 1

o a 5 joint anti- joint onti_shy~_____~ pouss iere i L-1) middot=e0 ~5 mm

10 vor r detoil ill he ( mm flg( c ) 60 he vor r

fr g con e

cone i

__de =_357mm_ l

( o l ( b l

Fig 1 ExempLe de penetrometre de reference a cone fixe (a) avec ou (b) sans manchon de Jrottement DetaiL du vide (c)

29

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

joalzomi tre

ett

-- shy

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HPa

0 7

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HPa

HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

32 COne le cOne doit ~tre constitue dune partie conique et dune prolongation cylindrique (fig 2) langle au sommet du cOne doit ~tre de 60deg

rugosite de surface ~1 ~m

Fig 2 Tolerances sur les dimensions du c6ne de reference

Pour le cOne de reference la longueur he de la prolongation cylindrique immediatement au-dessus de la partie conique ne depassera pas 10 mm Ceci vaut egalement pour le piezocoumlne avec element filtrant dans la prolongation cylindrique (fig 3)

fil t re

Fig 3 Piezoc6ne avec un element filtrant dans la prolongation cylindrique

La seetian A de la base du coumlne doit etre de 21000 mm conaringuisant aring un diametre du coumlne de 357 mm Le

diametre du coumlne est defini comme etant le diametre de la prolongation cylindrique

La rugosite de surface dans le sens longitudinal du coumlne ne depassera pas l ~m ce qui equivaut aring la rugosite produite par le frottement du sol

Tolerances sur les dimensions (voir note 4) (a) sur la seetian de la base du coumlne Ac

A 1000 mm 2 - 5 + 2

c

conduisant aring un diametre du coumlne de

348 mm i d i 360 mm c

Pour un coumlne usage le diametre du coumlne doit etre mesure aring

la seetian terminale de la prolongation cylindrique

(b) sur la hauteur hc de la partie conique du coumlne

240 mm i h i 312 mm c

(c) sur la hauteur he de la prolongation cylindrique

7 mm i h i 10 mm e

Les coumlnes presentant une usure asymetrique visible doivent etre rejetes

33 Vide et joint au-dessus du coumlne (fig 1) le vide entre le coumlne et les autres elements du penetrometre ne peut depasser 5 mm

Les limites exterieures du vide doivent avoir une forme telle que les mesures ne peuvent pas etre affectees par un pontage eventuel du vide par des particules de sol

Le joint qui est place dans le vide sera con~u et fabrique correctement pour prevenir et empecher que des particules de sol ne penetrent dans la pointe penetrometrique Il aura une deformabilite de beaucoup superieure aring celle du dispositif de mesure loge aring

linterieur de la pointe La seetian transversale du vide qui subsiste apres deduction de la partie occupee par le joint doit etre inferieure auml 10 mm 2 (figl)

3 4 Dispositif de mesure le dispositif de mesure de la resistance au coumlne et du frottement doit etre con~u de maniere telle quune excentricite de ces resistances ne puisse affecter les mesures Le dispositif de mesure du frottement local fonctionnera de maniere telle que seules les contraintes tangentielles et non les contraintes norshymales agissant sur le manchon de frottement soient mesushyrees

35 Manchon de frottement (fig 1b) le diametre du manchon de frottement ne peut etre inferieur au diametre de la base du coumlne La surface laterale du manchon de

2104frottement doit etre de 1 5 x mm bull

Tolerances sur les dimensions

(a) sur le diametre ds du manchon de frottement

d i d i d + 035 mm c s c

ou d est le diametre reel de la base du coumlne c

(b) sur la surface laterale As du manchon de frottement

104A = 1 5 x mm 2 + 2 - 2

s

caringd

2 mm

(c) sur la rugosite de surface r du manchon de frottement dans le sens longitudinal (voir note 5)

025 ~m i r i 0 75 ~m

Le manchon de frottement doit se situer immediatement aushydessus du coumlne (fig lb) Lespace annulaire entre le manchon de frottement et les autres elements de la pointe penetrometrique ainsi que les joints doivent satisfaire aux stipulations de la seetian 33

30

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

joalzomi tre

ett

-- shy

- 00001

--L-cOOc08

MPa

HPa

0 7

1 O

HPa

HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

36 Tubes de fon~age les tubes de fon~age doivent etre visses ou fixes les uns aux autres de maniere aring etre solidaires et aring former un train de tiges rigidement liees avec un axe rectiligne et continu La deviation aring mishylongeur dun tube de l m par rapport aring une droite passant par les extremites ne peut pas depasser (i) 05 mm au cas des cinq tubes inferieurs et (ii) l mm au cas des autres tubes

Pour nimporte quelle couple de tubes visses ou fixes lun aring l autre l a deviat i on aring lempl acement du joint par rapport aring une droite passant par les extr emites ne peut non plus depasser ces limites

3 7 Dispos itifs de aesure l e s resistances au coumlne et sur le manchon de frottement sil existe et l a pression deau interstitielle au cas dun piezocoumlne doivent etre mesurees au moyen de dispositifs adequats et les signaux doivent etre transmis par une methode adequate aring un enregistreur de donnees

Il nest pas recommande de nenregistrer les donnees dessai que sur bande qui ne permet pas un acces direct pendant lessai

38 Machine de fon~age la machine doit avoir une course dau mains un metre et elle doit foncer les tubes dans le sol aring une vitesse de penetration constante La machine doit etre ancree etou lestee de maniere aring ne pas se deplacer par rapport au sol lors du fon~age

3 9 Dispositif de reduction du frotteaent si un dispositif de reduction du frottement est utilise il doit etre situe au mains aring 1000 mm au-dessus de la base du coumlne

4 bull MODE OPERATOrRE

41 Essai en continu le mode operatoire est celui de lessai de penetration continue dans lequel les mesures sant faites alars que tous les elements de la pointe penetrometrique ont la meme vitesse de penetration

42 Verticalite Lamachine de fon~age est installee de fa~on aring fournir une direction de fon~age aussi verticale que possible La deviation de la direction de fon~age par rapport aring la verticale ne peut depasseer 2 Laxe des tubes de fon~age doit caincider avec laxe de la poussee

43 Vitesse de penetration la vitesse de penetration doit etre de 20 mmsee avec une tolerance de ~ 5 mmsee Au cas du piezocoumlne la tolerance doit etre diminuee Dans la limite de cette tolerance la vitesse de penetration doit etre maintenue eonstante pendant tout le temps de lenfoncement meme si des leetures ne sant faites que par intervalles

44 Intervalles de lecture une leeture continue est recommandee En aucun cas lintervalle entre les leetures ne peut depasser 02 m

45 Mesure de la profondeur les profondeurs doivent etre mesurees avec une precision dau mains 01 m

5 PRECISION DES MESURES

En prenant en compte toutes les sources derreurs possibles (frottement parasite des dispositifs denregistrement excentricite de la charge sur le coumlne ou le manchon differences de temperatures etc ) la precision de mesure ne peut etre mains bonne que la plus grande des valeurs suivantes

5 de la valeur mesuree 1 de l a valeur maximum de la resistance mesuree

dans l a couche consideree

La precision doit etre verifiee au laboratoire ou sur chantier en considerant toutes les i nfluences pertubatrices possibles (voire nate 6)

6 PRECAUTIONS CONTROLES ET VERIFICATIONS

61 Rectitude des tubes de fon~age la rectitude des tubes de fon~age et leurs joints doivent etre controumlles regulshyierement particulierement en ce qui concerne les cinq tubes inferieurs (voir sect36 et nate 7)

62 Usure lusure du coumlne du manchon de frottement et du fOt de la pointe penetrometrique doit etre controumllee regulierement

63 Distance aring dautres essais le CPT ne peut pas etre execute troppres de trous de forages ou dautres essais de penetration existants Il est recommande que des essais CPT de reference ne soient pas executes aring mains de 25 diametres de forage par rapport aring des forages ou aring mains de 2m de CPT executes anterieurement (voir nate 8)

6 4 Joints les joints entre les differents elements de la pointe penetrometrique doivend etre controles reguliereshyment pour sassurer de leur etat Avant usage les joints doivent etre verifies quant aring la presence de particules de sol et nettoyes

65 Campensatian de temperature les paintes penetrometriques electriques doivent etre equipees de compensateurs de temperature Si la deviation constatee apres extraction de la pointe est telle que la precision definie aring la seetian 5 nest pas atteinte lessai doit etre rejete en tant quessai de reference

7 ETALONNAGE

71 Manometres l es manometres doivent etre etalonnes au mains tous les 6 mois Pour chaque type de manometre on doit disposer de deux exemplaires identiques chacun avec son propre etalonnage A intervalles reguliers on doit verifier le manometre utilise pour les essais par camparaison avec le manometre de reserve

7 2 Pesonsanneaux dynaaoaetriques les pesons et les anneaux dynamometriques doivent etre etalonnes au mains tous les 3 mois Il est recommande deffectuer des controumlles reguliers sur chantier avec un appareillage de controumlle approprie

8 DISPOSITIFS SPECIAUX

81 Guidage des tubes de fon~age pour eviter le flambement il doit etre prevu un guidage de la partie des tubesse trouvant hors-sol ou dans leau

31

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

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INTERSTITIELLE 0 2 0 4 0 6

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Q lt(

z -10 l Qlt(

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0 lt( Q

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-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

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DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

82 Incl~tres afin de suivre les deviations des tubes de fon~age dans le sol la pointe penetrometrique peut ~tre equipee dinclinometres

La necessite de disposer dune telle information depend des sols rencontres et cro1t avec la profondeur dessai

83 Tubes de fon~age de plus petit diaaetre Afin de diminuer le frottement lateral sur les tubes on peut utiliser des tubes de fon~age de diametre inferieur aring

celui de la pointe La distance entre les tubes de plus petit diametre et la base du coumlne doit ~tre au moins de 1000 mm

84 Piezocoumlne la pointe peut etre equipee dun dispositif de mesure de la pression deau interstitielle en liaison avec un filtre place dans la partie conique ou dans la prolongation cylindrique voir note 9) Le filtre et tous les canaux du piezocoumlne doivent ~tre remplis deau ou dun autre fluide approprie et convenablement desaeres avant chaque ensemble dessais Des preeautians doivent etre prises pour maintenir la complete saturation du filtre et des autres espaces du systeme de mesure au cours du transhysport vers le site dessai et au cours de lexecution de lessai de penetration au piezocoumlne specialement lorsque les couches superieures ne sent pas saturees

9 PRESENrATION DES RESULTATS

Les resultats doivent ~tre portes e graphique donnant en fonction de la profondeur la variaton de qc et eventuellement fs Rf (If) etou Qt etou Qst etou u

91 Les informations suivantes doivent etre consignees

- sur les graphiques des essais

l Lorsque le penetrometre et le mode operatoire sent en tous points conformes au mode operatoire de reference chaque graphique doit ~tre marque de la lettre R (mode operatoire de ~eference) Cette lettresera suivie de lune des lettres suivantes qui indique lesystemede mesure

M mecanique E electrique H hydraulique

Les capacites des differents dispositifs de mesure doivent etre consignees

2 La date et lheure de lessai et le nom de la societe

3 Le numera dindentification du CPT et sa situation sur le site

4 La profondeur aring partir de laquelle on a utilise un dispositif de reduction du frottement ou des tubes de diametre reduit La profondeur aring laquelle on a remante les tubes sur une certaine hauteur afin de reduire le frottement lateral et de permettre une penetration jusquaring plus grande profondeur

5 Toute interruption anormale dans le deroulement de lessai de reference ainsi que toute interruption dans lessai au piezocoumlne

6 Les observations faites par loperateur portant sur le type de sol les bruits en provenance du train de tubes la presence de pierres les anomalies etc

7 Les indications relatives aring lexistence et lepaisseur de remblais ou aring lexistence et la profondeur dexcavations et le niveau de depart de lessai CPT par rapport aring la surface du terrain naturel ou modifie

8 La coumlte de la surface du sol aring lemplaeement de lessai

9 Au cas de lemploi dun piezocoumlne lindieation claire quant aring la position la dimension et le materiau eonstitushytif du filtre

10 Les leetures aring linelinometre au eas ou ees leetures ont ete faites

11 La leeture zero de tous les eapteurs avant et apres lessai

12 Toutes les verifications faites apres extraetion des tubes de fon~age letat des tubes de fon~age et de la pointe penetrometrique

13 La profondeur de leau dans le trou subsistant dans le sol apres extraetion du penetrometre ou la profondeur aring laquelle le trou sest eboule

14 Si le trou de lessai a ete rebouehe et si oui par quelle methode

92 Outre les informations reprises aring la seetian 91 il doit etre Consigne au dossier

1 Lidentifieation de la pointe penetrometrique utilisee

2 Le nom du responsable de lequipe ayant realise lessai

3 Les dates et numeros des eertifieats detalonnage des appareils de mesure

93 Pour la representation des resultats de lessai sous forme graphique il est reeommande dutiliser les rapports suivants entre les echelles de laxe vertical et de laxe horizontal

Eehelle de profondeur axe vertieal 1 longueur unitaire (arbitraire) pour 1 m

Resistanee au eoumlne qe axe harizontal la meme longueur unitaire pour 2 MPa

Frottement lateral loeal f axe harizontal s

la meme longueur unitaire pour 50 kPa

Effort total denfoneement Qt axe harizontal la meme longueur unitaire pour 5 kN

Effort total de frottement Qst axe harizontal la m~me longueur unitaire pour 5 kN

Pression de leau interstitielle axe horizontal la meme longueur unitaire pour 20 kPa

- sur les diagrammes ou dans le rapport

32

-RESISTANCE DE CDNE EN MPgt fROTTEHENT LtJCAL EN HPa POURCENT AGE DE FROT TE MENT EN

bull10 o --shy PRESSION D EAU

20 40 60 0 0 0 2 0 4 bull10 t---t-----1

o middot10

10

INTERSTITIELLE 0 2 0 4 0 6

l O 1 NP~-=10m de cotonne deau

Q lt(

z -10 l Qlt(

0 o Q Q lt( 0

0 lt( Q

~ 0 -20 - 20 w o z

o

0 Q

-30 - 30 +---------- -30~---~--~

RENAROUES Oimbullnsions du fbullLt r a h01utaur 3Om m tpi 1S SIur 3 0mm Pos itio n du f1l trt bullm~ridutement au-d ess us du coumlne H01 ttn01u du f1L trbull Hler inoxydible

prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

j moumln(hon de fr

joalzomi tre

ett

-- shy

- 00001

--L-cOOc08

MPa

HPa

0 7

1 O

HPa

HP~ 7 kPa

kPa

DfLF T GEOTECHNJCS HA81TATIONS A HAAS ~LUIl

fS -4 1 DE PENETRitTR C V 4 U (OVE GO OJfR[I

Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

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prlcision l e c tur e d t l cOumlcncbull middot_O_O_2 l ror -----f-----j-- IO___M_P_bull-+_10_0_MP_bull__-J_SOO__k_P_bull-j___

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Comme des valeurs sont uniquement recommandees pour le rapport des echelles la longueur unitaire sur laxe vertical peut etre choisie arbitrairement de sorte aring ce que des feuilles de dimensions standardiseeg puissent etre utilisees voir fig 4

94 Plan de situation

Pour chaque investigation un plan de situation tres clair doit etre dresse avec des points de reference clairement indiques afin que lemplacement des essais soit defini avec precision

Dans le cas ou la reconnaissance comporte aring la fois des essais de penetration et des forages la sequence dexecution doit etre indiquee

Oispositd de reduction du frottement non utrtisli ln terrupt io ns anormoales niant Ubserv01tions nli01nt Rembl01i dlblo~i rembl01i 01ncicntm d ipa rs sc ur lndinomRtre pis de mesures Etat du tubes de fon~aga et de ta pointe plinaringtrom~trJqull 01pr8s ess01 i bon Niveilu de t au dns le trou de sondage lrou ilb oulQ pris de l surfilce Bouchilgll du trou ne nt Prl cision des dispos i tifs de mesure

10 DIVERGENCES PAR RAPPORT A LESSAI DE REFERENCE

101 Generalites

Toute divergence par rapport aring lessai de reference doit etre decrite completement et explicitement sur le diagramme donnant les resultats de lessai

Les divergences possibles sont

102 divergence de la dimension du coumlne

103 divergence de langle au sommet du coumlne

104 divergence des dimensions du manchon de frottement

105 divergence de la localisation du manchon de frottement

106 divergence liee aring la forme de la pointe penetrometrique

107 divergence liee aring la possibilite de mauvements relatifs du coumlne par rapport aux tubes de foncage (pointes dites aring coumlne mobile)

33

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

~15mm

tf1

618mm

tl30mm

Fig 11 Pointe penetrometrique hollandaise a manchon de frottement

--1-+++gtltlSmm

~++o__c_13 mm

Fig 12 Pointe penetrometrique a c6ne simple

Fig 13 Pointe penetrometrique a c6ne a jupe dURSS

1092 Tiges interieures

Le diametre des tiges interieures doit etre de 05 aring l mm inferieur au diametre interieur des tubes de foncage Les tiges interieures doivent glisser de facon aisee dans les tubes de foncage

Les extremites des tiges interieures doivent etre exactement perpendiculaires aring laxe de la tige et usinees de sorte aring obtenir une surface lisse

Les tiges interieures ne peuvent etre assemblees ni par vissage ni par tout autre moyen afin de leur laisser un degre de liberte il a en effet ete constate que tout assemblage augmente le frottement parasite entre les tiges et les tubes Avant et apres essai il doit etre controumlle que les tiges interieures glissent aisement dans les tubes de foncage et egalement que le coumlne et le manchon de frottement se deplacent facilement par rapport au corps de la pointe penetrometrique Pour augmenter la precision pour les faibles valeurs de la resistance les mesures deffort enregistrees en surface doivent etre corrigees du poids cumule des tiges interieures en ce qui concerne la resistance au coumlne et du poids cumule des tubes de foncage et des tiges interieures en ce qui concerne leffort total

36

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

1010 Precision des mesures

Lorsque lessai execute diverge par rapport auml lEssai de Reference deux classes de precision sant definies

Precision normale voir seetian 5 Precision basse la precision obtenue ne sera pas mains bonne que la plus grande des valeurs suivantes

10 de la valeur mesuree 2 de la valeur maximum de la resistance mesuree

dans la couche consideree

Dans tous ces cas la classe de precision de lessai doit etre indiquee dans le rapport et sur les diagrammes

1011 Penetrometres statiquesdynamiques et penetrometres preforeurs

La penetration peut etre accrue par lusage de penetroshymetres statiques dynamiques et egalement par lusage de penetrometres equipes doutils de preforage Lusage de tels appareils doit etre indique clairement dans le r apport et sur les diagrammes

11 NOTES EXPLICATIVES ET COMMENTAIRES

bull Nate 1 Definitions (211)

Les denaminations continue et discontinue appliquees aux essais de penetration ne sant pas tout auml fait correctes Les termes avec foncage sant plus explicites Cependant les termes continue et discontunue ont ete rnaintenus parce quils sant deja dun emploi generalise

bull Nates 2 Definitions (216)

Le pourcentage de frottement Rf (rapport du frottement lateral local f aring la resistance au caringne

s qc) doit etre exprime en pour-cents afin dobtenir un nombre plus grand que lunite Bien que par le passe ce soit ce rapport qui ait ete le plus utilise on peut egalement utiliser lindice de frottement If (rapport de la resistance au caringne qc au frottement lateral

local f l d d b l que lu~1 t~~1 onne irectement un nom re pus grand

Il doit etre pris soin de calculer le pourcentage de frottement et ou lindice de frottement pur des mesures de resistance au caringne et de frottement lateral local prises aring

la meme profondeur Bien que ceci soit clairement dit dans la definition donnee en 216 lattention est attiree sur l e fait quen raison de lecart en profondeur entre le caringne et la manchon de frottement ces pararnetres ne peuvent pas etre calcules aring partir des mesures faites au meme instant

bull Nate 3 geometrie generale de la pointe penetrometrique (31) du caringne (32) du vide et du joint au-dessus du caringne 33) et du manchon de frottement 3 5)

Au cours de la penetration des pressions deau agissent en sens oppeses sur les faces terminales du caringne Lorsque celles-ci sant de seetians inegales il peut en resulter une difference dans la resistance au caringne mesuree qui depend de la valeur de la pression deau Baligh et al 1981) Ceci vaut aussi pour le manchon de frottement Pour

tenir compte de cette influence la geometrie peut etre definie plus completement notamment par le rapport des aires (RG Campanella PK Robertson D Gillespie 1983) o

bull Nate 4 Tolerance sur les dimensions du caringne (32)

Dans les rares cas ou un nouveau caringne est use au-dela des limites prescrites au cours dun seul essai les resultats de lessai ne doivent pas etre rejetes

bull Nate 5 Manchon de frottement (35)

La rugosite est definie par lecart moyen de la surface reelle dun corps par raport au plan moyen La rugosite es t exprimee en micrometres (~m)

bull Nate 6 Erreurs possibles 5 1010)

Apres execution de lessai il est parfois nate un non re tour auml zero Le total de cette erreur combinee avec les aut res erreurs possibles ne peut pas depasser les limites de precision prescrites aux seetians 5 et 1010

bull Nate 7 Contraringles 61)

Les tubes de foncage doivent etre controles au mains apres lexecution dessais sur une certaine profondeur cumulee disans 500 m

Ils doivent etre contraringles apres chaque essai dans certaines conditions de sol qui sant connues pour conduire aring l a flexion des tubes par examples

(a ) de grandes epaisseurs de sols tres mous surmontant des couches dures

b ) des sols residuels contenant des blocs errants (c ) des sols contenant de gros graviers et des cailloux

bull Nate 8 Distance aring daures essais 63)

Lorsquun CPT et un forage doivent etre executes aring

proximite lun de lautre il est recommande chaque fois que la chose est possible dexecuter le CPT avant dexecuter le forage Ceci a de surcroit lavantage que l es niveaux ou des echantillons de sol doivent etre preleves peuvent etre selectionnes en fonction des conditions de sol

Commes guide un essai CPT profond est un essai qui atteint une profondeur de 10 m ou plus

bull Nate 9 Penetrometre piezocaringne 84)

Avec le piezocone la pression deau interstitielle existant dans le sol adjacent au caringne est mesuree de facon continue pendant la penetration La pression interstitielle mesuree est la samme de la pression interstitielle positive ou negative qui sy rajaute et qui resulte de la tendance aring la compression ou aring la dilatance du sol due a la penetration

Lexperience et letat des connaissances relatifs au piezocone sant eneare assez limites Cest la raison pour laquelle il apparait premature de presenter des

37

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

recommandations quant aring ses particularites Neanmoins le sous-comite a decide de donner quelques recommendations generales quant aring la localisation du filtre et quelques autres aspects importants de sorte aring obtenir une uniformite raisonnable dans les publications

En selectionnant la localisation du filtre immediatement au-dessus de la base du coumlne dans le prolongement cylindrique he (fig3) la majorite des applications dans la pratique a ete suivie Cependant ceci doit etre considere comme un projet de recommandation En raison du choix de cette localisation la longueur maximum recommandee pour he est portee aring 10 mm Linfluence de ce changement sur la resistance au coumlne est generalement faible et il est possible dapporter la correction correspondante

Le filtre doit etre constitue dun materiau resistant aring lusure Sa structure doit etre telle quil soit tres peu probable quil vienne aring etre bloque par des particules de sol Le dispositif de mesure des pressions deau interstitielles qui comprend element de mesure et son logement le filtre et les canaux de liaison doit avoir une courbe caracteristique tres raide en raison de la grande incidence sur a) la transmission de la pression deau interstitielle du sol aring element de mesure et b) le fait dempecher la penetration dans le filtre de fines particules de sol Il faut attendre les developpements subsequents

bull Note 10 Pointes penetrometriques aring coumlne mobile 10 7)

Il nest pas recommande deffectuer lessai de penetration continue avec un penetrometre mecanique quand on desire une bonne precision ear le mouvement relatif des tiges interieures par rapport aux tubes de fon~age peut changer de sens avec la profondeur augmentant ainsi la marge derreur due aux frottements internes parasites En outre il est necessaire de controumller au moins tous les metres au cours de la penetration que les tiges interieures sont toujours libres de se mouvoir par rapport aux tubes de fon~age

bull Note 11 Essai discontinu (107)

Au cas de pointes penetrometriques mecaniques et en vue detre certain que le coumlne et le manchon de frottement se deplacent suffisamment par rapport aux tubes de fon~age il soir etre tenu compte de fa~on effective du raccourcissement elastique des tiges interieures Pour cela le mouvement des tiges interieures en surface par rapport aux tubes de fon~age doit etre au moins egal aring la somme du mouvement minimum requis pour le coumlne (voir section 109) et du raccourcissement elastique des tiges interieures

bull Note 12 Coumlne simple 107 fig 12)

Dans le cas du coumlne simple des preeautians doivent etre prises contre lentree de sol dans le mecanisme de glissement et affectant les mesures de resistance Apres extraction de la pointe penetrometrique un controumlle doit etre effectue en vue de sassurer que la tige du coumlne est toujours tout aring fait libre de sa mouvoir par rapport aring son guide

38

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

APPENDICE B

METHODE DESSAIS DE REFERENCE INTERNATlONALE POUR LESSAI DE PENETRATION STANDARD (SPT)

1 PORTEE

11 Ce document decrit les principes constitutant des mathodes dessai acceptables pour lessai SPT dont les resultats soient comparables

12 Lessai SPT determine aring la base dun trou de sonde la resistance aring la penetration dun carottier tubulaire en acier et permet la recuperation dun echantillon disloque aux fins dindentification On peut alars etablir la relation entre la resistance aring la penetration et les caracteristiques et la variabilite des sols

Le principe de base de lessai consiste auml laisser tomber dune hauteur de 760 mm un marteau pesant 635 kgf sur un manchon de battage Le nombre de coups (N) necessaires pour atteindre une penetration du carottier de 300 mm (apres sa penetration sous leffet de lagravite et enshydessous dun enfoncement damorcage) est considere comme la resistance auml la penetration (N)

2 DEFINITION$

21 SPT est labreviation de l Essai de Penetration standard decrit dans cette methode dessai de reference

22 Carottier ensemble dacier tubulaire constitue des elements decrits dans la seetian 32

23 Tiges de liaison tiges dacier reliant le carottier au manchon de battage

24 Ensemble marteau les elements du materiel qui servent aring enfoncer le carottier dans le sol et qui comprennent un manchon de battage un guide et un mecananisme degagement

2 5 Manchon de battage enclume dacier fixeeau sammet des tiges de liaison par un filetage Cette enclume est une partie interne de certains ensembles marteaux appeles marteaux de securite Dans ce cas le tige rattachee aring lensemble est vissee sur les tiges de liaison

26 Marteau corps dacier pesant 635 kgf

27 Guide tige dacier assurantun guidage uniforme du marteau pendant toute sa chute libre de 760 mm

28 Mecanisme de degagament dispositif de liberation mecanique du marteau assurant sa chute libre eonstante de 760 mm

29 Enfoncement damorcage le nombre de coups necessaires pour la penetration initiale du carottier de 150 mm

210 Enfoncement dessai le nombre de coups necessaires apres lenfoncement damorcage pour une penetration supplementaire de 300 mm

3 MATERIEL

31 Appareil de forage

311 Lappareil de forage sera capable dassurer un trou net permettant deffectuer lessai de penetration sur un sol essentiellement non perturbe

312 En forage aring injection un trepan aring evacuation laterale sera utilise et non un trepan aring evacuation par le fond Le procede employant linjection aring travers un carottier aring tube ouvert suivie de lessai une fois que la profondeur voulue est atteinte ne sera pas autorise

31 3 Si le forage est effectue aring la tariere cuiller avec tubage temporaire le diametre des outils de forage ne devra pas etre superieur aring 90 du diametre interieur du tubage

314 Le diametre du trou desonde devra etre aussi petit que possible et campris entre 63 et 150 mm

32 Carottier

Le tube du carottier devra etre en acier trempe avec des parais interieure et exterieure lisses Le diametre exterieur devra etre de 51 mm plusmn l mm et le diametre interieur devra etre de 35 mm t l mm sur toute la longueur Sa longueur devra etre de 457 mm minimum

Lextremite inferieure du tube devra camporter un sabot dattaque dune longueur de 76 mm l mm ayant les memes diamatres interieur et exterieur que le tube Sur ses 19 mm inferieurs le sabot aura une forme conique uniforme Un bord tranchant devra etre evite comme illustre aring la Fig l Le materiau du sabot sera le meme que celui du tube

Lextremite super1eure du tube devra etre munie dun accouplement dacier qui l e raccordera aux tiges de liaison A linterieur de laccouplement sera prevu un clapet anti-retour et ses parois camporteront de grands orifices devacuation permettant aring lair ou aring leau de sechapper librement lors de lentree de lechantillon Le clapet devra assurer un joint etanche lors du retrait du carottier

Le sabot dattaque devra etre remplace lorsquil sera endoromage ou deforme et la carottier devra etre propre et exempt dincrustations de sol tant aring linterieur quaring lexterieur

Une forme acceptable de carottier est representee aring la Fig l

39

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

Fig 1 Coupe du carottier de lessai SPT

33 Tiges de liaison

331 Les tiges de liaison en acier reliant le carottier au manchon de battage devront avoir un module de seetian approprie aring leur longueur totale et aring la contrainte laterale

La seetian pourra avoir les proprietes suivantes

Diametre de Module de Poids de la tige (mm) section t i ge

3(x 10- 6 m ) (kgfm)

405 428 433 50 859 723 60 1295 1003

Il ne devra pas etre utilisees des tiges dun poids superieur aring 1003 kgfm

332 Seules devront etre utilisees des tiges droites et des controles periodiques devront etre effectues sur place Mesuree sur la longueur totale de chaque tige la deviation relative ne devra pas etre superieure aring 1750

333 Les tiges devront etre raccordees etroitement par des joint aring vis

34 Ensamble marteau

341 Lensemble marteau devra comprendre

a Un manchon de battage visse serre au sammet des tiges de liaison Ce pourra etre une partie interieure de lensemble comme dans les marteaux de securite Lenergie transmise lors de limpact devra etre maximisee par une conception appropriee du manchon de battage

b Un marteau dacier dun poids de 635 kgf (plusmn 05 kgf) o

c Un guide assurant la chute du marteau avec le minimum de resistance

d Un mecanisme de liberation mecanique assurant une chute libre eonstante du marteau de 760 mm

342 Le poids total de la partie de lensemble marteau qui repase sur les tiges de liaison ne devra pas depasser 115 kgf

343 Dans les situations ou des camparaisens des resultats dSPT sant importantes des etalonnages devront etre effectues pour evaluer le rendement du materiel en ce qui concerne le transfert de lenergie Dans ces cas-laring les valeurs de N devront etre ajustees aring un etalon egal aring 60 de lenergie cinetique nominale dans un marteau de 635 kgf apres une chute libre de 760 mm soit 474 Joules Lenergie de reference sera mesuree immediatement en-dessous du manchon de battage

4 METHODE DESSAI

41 Peeparation du trou de sondage

411 Le trou de sondage devra etre soigneusement nettoye jusguaring la hauteur de lessai aring laide dun equipement qui ne perturbe pas le sol devant subir lessai Pour le forage dans les sols ne permettant pas aring un trou de rester stable un tubage etou du fluide de forage aring la bentonite devront etre utilises Il ne devra pas etre utilise de tubage aring tige creuse pour les essais enshydessous de leau souterraine

412 Pendant le forage en-dessous de la nappe phreatique la surface de leau ou du fluide de forage dans le trou de sondage devra etre constamment maintenue aring une distance suffisanteau-dessus de niveau de leau souterraine pour miniroiser la perturbation Le niveau de leau ou du fluide de forage dans le trou de sondage devra etre maintenu pendant le retrait des outils de forage ettout au long de lessai pour assurer lequilibre hydraulique aring la hauteur de lessai

413 Les outils de forage par ex lenveloppe devront etre retires lentement pour eviter que les effets de aspiration nameublissent le sol devant subir lessai

41 4 Si un tubage est utilise il ne doit pas etre enfonce en-dessous de niveau auquel doit commencer lessai

42 Execution de lessai

42 1 Le carottier devra etre abaisse jusquau fond du trou de sondage sur les tiges de liaison surmontees de lensemble marteau La penetration initiale sous ce poids mort total devra etre notee Si cette penetration depasse 450 mm lenfoncement dessai sera omis et la valeur N sera consideree comme zero

Apres la penetration initiale lessai sera execute en deux phases

Enfoncement damorcage Le carottier sera enfonce aring une profondeur de penetration de 150 mm dans le sol et le nombre de coups necessaires pour atteindre cette penetration sera note Si la penetraiton de 150 mm ne peut etre atteinte en 50 coups la profondeur de penetration atteinte apres 50 coups sera notee et dans ce cas cest la profondeur qui sera donc enregistree comme enfoncement damorcage

Enfoncement dessai Le nombre de coups necessaires pour les 300 mm de penetration suivants est appele resistance aring la penetration (N) Le nombre de coups necessaires pour atteindre chaque increment de 150 mm de penetration sera note Lenfoncement dessai pourra etre arrete apres 50 coups dans lun ou lautre des increments de 150 mm ou bien la profondeur de penetration obtenue sera enregistree si lessai est arrete aring 50 coups

40

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

La cadence des coups de marteau ne devra pas etre excessive au point quelle risque dempecher le marteau datteindre la chute standard ou les conditions dequilibre de setablir entre les coups successifs La cadence maximum typique du battage est de 30 coups par minute

43 Recuperation de lechantillon de sol et etiquetage

431 Le carottier sera remante aring la surface et ouvert Le ou les echantillons representatifs du sol contenus dans le carottier seron places dans des recipients hermetiques

432 Des etiquettes portant les renseignements suivants devront etre apposees sur les recipients

a Site b Numero du trou de sondage c Numero dechantillon d Profondeur de penetration e Longueur dechantillon f Date de lessai g Resistance standard aring la penetration (N)

5 RAPPORT DES RESULTATS

Les renseignements suivants devront figurer dans le rapport

l Site 2 Date du forage jusquaring la profondeur dessai 3 Date et heure de debut et de fin de lessai 4 Numero du trou de sondage 5 Methode de forage et diametre de base du trou de

sondage presence ou non deau ou de fluide de forage dans le trou

6 Dimensions et poids des tiges de liaison utilisees pour les essais de penetration Le poids de manchon de battage devra aussi etre indique

7 Type demarteau et de mecanisme de liberation 8 Hauteur de la chute libre 9 Profondeur au fond du trou de forage (avant

l essai) 10 Profondeur au fond du tubage

11 Informations sur le niveau deau souterraine et le niveau deau ou de fluide de forage dans le trou de sondage au debut de chaque essai

12 Profondeur de penetration initiale et profondeurs entre lesquelles ont ete mesurees les resistances aring la penetration (enfoncements damorcage et dessai)

13 Nombre de coups nessaires pour chaque increment successif de 150 mm de penetration (pour lenfoncement damorcage et pour lenfoncement dessai) par ex 121516 La profondeur de penetration atteinte devra etre indiquee si lessai est arrete aring 50 coups par ex 204550 - 100 mm ou 3050 - 75 mm

14 Description des sols identifies dapres les echantillons recuperes dans le carottier

15 Observations concernant la stabilite des couches soumises aring essai ou des obstacles rencontres au cours des essais etc qui faciliteront interpretation des resultats dessai

16 Resultats des essais detalonnage le cas echeant (Clause 343)

6 ANNEXE

Variations par rapport aring lessai de reference

(i) Le document intitule Standard Penetration Test (SPT) International Reference Test Procedure (Essai de Penetration Standard (EPS) Methode dEssai de Reference Internationale) et presente par le groupe de travail aring ISOPT-1 Orlando USA les 20-24 mars 1988 identifiait des variations dans le materiel et les methodes developpees par les pays membres de lISSMFE

(ii) Les variations indiquees ci-dessous sont representatives de la situation et des tendances actuelles

a Diametre interieur du cylindre du carottier superieur de 3 mm au diametre interieur standard de 35 mm du sabot dattaque (USA)

b Utilisatian dun coumlne dacier plein au lieu du sabot dattaque standard pour les essais dans les graviers et les roches friables (Royaume-Uni et Australie)

c Elimination de linfluence des tiges de liaison par positionnement dun marteau immediatement au-dessus du carottier (M E Schultze (1961) Contributian aring la discussion 5eme convention internatianale de lISSMFE Paris Vol III p 183

41

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

APPENDICE C

PROCEDURES INTERNATIONALES DESSAI DE REFERENCE AU PENETROMETRE DYNAMIQUE (DP)

l OBJET

Lexpression sondage est utilisee pour souligner que lessai comporte une mesure continue contrairement par exemple aring lessai SPT Le but de la penetration dynashymique est de mesurer lenergie necessaire pour enfoncer une pointe dans le sol et obtenir ainsi des valeurs de resistance qui earrespondent aux proprietes du sol Quatre proeectures sant acceptees

Le sondage au penetrometre dynamique leger (DPL regroupant le domsine des masses peu elevees des penetroshymetres dynamiques en Utilisatian internationale la proshyfondeur de linvestigation normalement ne depasse pas 8 metres environ pour pouvoir obtenir des resultats valabshyles

Le sondage au penetrometre dynabulllique 110yen (DPM regroupant le domsine daes masses moyennes la profondeur de linvestigation normalement ne depasse pas 20 aring 25 metres environ

Le sondage au penetrometre dynamique lourd (DPH regroupant le domsine des masses moyennes aring tres lourdes la profondeur de linvestigation ne depasse normalement 25 metres environ

Le sondage au penetrometre dynamique tres lourd (DPSH) regroupant le domaine des masses tres elevees des peneshytrometres dynamiques et analoques aring celles du SPT la profondeur de linvestigation peut depasser les 25 metres

2 DEFINITION

21 Principes genereaux et nomenciature

Un mouton de masse M et dune hauteur de chute H est utilise pour enfoncer une pointe conique Le mouton frappe une enclume qui est parfaitement solidaire du train de tiges La resistance de penetration est definie par le nombre de coups necessaire pour un enshyfoncement sur une profondeur donnee Lenergie de frappe est egale au produit de poids du mouton par la hauteur de chute (M gH) Les resultats des differents types de penetration dynamique peuvent etre exprimes (etou campares) par des valeurs de resistance dynamique conshyventionelle qd ou rd voir nate l seetian 10)

Lutilisation principale de la penetration dynamique conshycerne les sols pulverulents Dans le cas des sols coshyherents ou dessais aring grande profondeur il faut etre tres prudent dans interpretation des resultats obtenus ear le frottement lateral parasite peut etre tres important (voir seetian 7 La penetration dynamique peut permettre de detecter des couches molles dans les sols pulverulents et de localiser des couches resistantes par exemple dans des sols pulverulents pour des pieux sollicites en pointe (DPH DPSH) En earrelation avec des sandages tests (key borings le type du sol et le contenu de cailloux et

de blocs (cobble and boulder) peuvent etre caracterises dune maniere acceptable Les resultats du DPL peuvent egalement etre utilises pour evaluer la ripabilite et louvrabilite workability des sols

Apres un etalonnage correct les resultats du sondage au penetrometre dynamique peuvent etre utilises pour obtenir une indication des caracteristiques utiles pour le genie civil (engineering properties comme pe

- densite relative - compressibilite - resistance au eisailiement - consistance

A ce jour linterpretration quantitative des resultats y campris predietians de la force portante reste limitee principalement aux sols pulverulents il faut tenir compte du fait que le type du sol pulverulent (distribushytion de la taille du grain etc) peut influencer les reshysultats du sondage

22 Classification

Quatre methodes differentes de sondage les types DPL DPM DPH et DPSH sant acceptees pour sadapter aux conditions topographiques et geologiques differentes et aux divers but de linvestigation

Appareillage proeectures de sondage mesures et enshyregistrement sant decrits dans les seetians suivantes Des donnees techniques sant resumees en tableau l Daushytres types dequipement peuvent etre prevus pour des proshyblemes specifiques ou pour differentes dimensions de pointe voir seetian 9

3 EQUIPMENT

31 Equipement de battage

Lequipement de battage camprend le mouton lenclume et la tige guide Le tableau l indique les dimensions et les masses

Le mouton doit camporter un trou axial dant le diametre est de 3 aring 4 mm plus grand que celui de la tige guide Le rapport entre la longueur et la diametre du mouton cyshylindrique doit etre campris entre l et 2 Le mouton doit tomber librement et il ne peut camporter aucun element qui puisse influencer son acceleration et sa decelerashytion La vitesse initiale doit etre negligeable quant le moutonest libere de sa position haute (voir seetian 6)

Lenclume doit etre parfaitement solidaire du train de tige Le diametre de lenclume ne doit pas etre inferieur aring 100 mm ni superieur aring la maitie du diametre du mouton Laxe de lenclume de la tige guide et du train de tiges doit etre rectiligne avec une deviation maximale de 5 mm par metre

42

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

Tableau 1 Resultats de sondageau penetrometre dynamique

Procedure de l essai de re te rence Facteurs

DPL DPM DPH DPSH

Masse du mouton en kg 1 o o 1 30 o 3 50 bull o 5 63 5 bull o 5

Hauteur de chute en m o 5 o o l O 5 plusmn o o l o 5 bull o o l o 75 bull o 02

Hasse de l enclume et de 18 18 30 tige guide (max) en kg

Rebond tnaximum en 50 50 50 50

Rapport longueur D) sur bull1 2 bull1 2 gt1 lt2 gt1 s2 diamtre du mouton

Diamtre de le nclume (d) 1OOSdSQ 50 100SdS050 1 OOsdsO 50 1OO~dSO 50

Lon g ue ur de la tige en m 1 o 1 1-2 bull o u 1-2 bull o 1 1-2 plusmn o 1 Hasse maxi male dune tige en kgm

Courbure maximale tige o 1 o 1 o 1 o 1 lt Sm en

Courbure maximale tige o 2 o 2 o 2 o 2 gt Sm en

Excentricite maximale des o 2 o 2 o 2 o 2 tiyes e n

Di amEtre de la t i ge 22 bull o 2 32 bull o 3 32 bull o 3 32 bull o 3 ter ieure

Diametre de la tig e in- bull o 2 9 bull o 2 9 bull o 2 t~ r ieure

Angle au sommet 90 90 90 90

s u r face de la poi nte la 1 o 10 15 20 base en cm2

Di arnetre d une pointe 357 plusmn o 3 357 plusmn o 3 437 plusmn o 3 51 plusmn o 5 neuve en mm

Diamitre d une pointe 34 34 42 49 usagee en rrm

Longueur cylindrique de 357 plusmn 1 357 plusmn 1 4 3 7 plusmn 1 51 bull 2 la pointe en nvn

Angle de raccordement a 11 11 11 11 la face sup r ieure de la pointe en degre

Longueur de l a partie 17 1 bull o 1 179 bull o 1 219 plusmn o 1 253 plusmn o 4 n i q ue de la pointe en

Us u re maximale de la parshytie c o nique de la pointe long ueur en rrvn

Nomb~e ~ de c~ ups par 10 cm 1 0cm 10 cm N1o 20 cm N20

l N10 N10

de penetratlon

Domaine stand ard du 3 - 50 3 - 50 3 - 50 5 - 100 nomb re de coups

50 150 167 238

3 2 Train de t iges

Le tableau l indique les dimensions et les masses du train de tiges Les tiges doivent etre en acier de haute resistance au choc aring lusure et aring la fatigue et de grande solidite aring basse temperature Les deformations permanentes doivent pouvoir etre rectifiees Les tiges doivent etre bien droites Des tiges pleines peuvent etre utilisees des tiges creuses sont aring preferer afin de r eduire le poids (voir seetian 6 Les joints des tiges ne doivent pas presenter dasperites (voir seetian 6

33 Pointes

Le tableau l indique les dimensions des pointes La pointe comporte une partie conique (tip une extension cylindrique et une transition conique dune longueur egale au diametre de la pointe entre lextension cylindshyrique et la tige (figure 1 Les paintes neuves doivent avoir une partie conique dont langle au sommet est de 90deg

Le tableau l indique le maximum dusure tolere de la pointe La pointe doit normalement etre attachee aring la tige de fa90n quelle ne puisse pas etre perdue pendant le battage On peut utiliser des paintes fixes ou des paintes perdues (detachables

Q l D

Fig 1 Schema de pointes et de tiges (le tableau 1 precise les dimensions D ~ diam~tre de la pointe)

4 PROCEDURE D ISSAI

41 Generalite

Les criteres darret du sondage doivent etre definies aring lavance

La profondeur requise peut dependre des conditions leeales et du but de lessai particulier

42 Equipement penetrometrique

Lessai penetrometrique doit etre effectue verticalbull~ ut en labsence de toutes autres specifications Lequipeshyment penetrometrique doit etre stable La pointe et le train de tiges doivent etre guides au debut de lessai afin de maintenir les tiges verticales Un avant-trou peut etre necessaire

Le diametre du trou de battage doit etre legerement plus grand que celui de la pointe Lappareillage dessai es t mis en station de telle fa9on qu il soit impossible que le train de tiges puisse flechir au-dessus du sol

43 Battage

Le penetrometre doit etre battu en continu dans le sol (subsoil La cadence devrait etre comprise entre 15 et 30 coups par minute sauf si par sondage ou identification acoustique la penetration dans le sable ou gravier est evidente dans ce cas la cadence de battage peut etre augmentee jusquaring 60 coups par minute Lexperience a montre que la cadence de battage na quune influence mineure sur les resultats dans de tels sols

Toute interruption doit etre notee sur la feuille des shysai Tous les facteurs qui peuvent influencer la resisshytance aring la penetration (pe la raideur du eauplage des tiges rigidite du train de tiges doivent etre controles regulierement Toutes modifications de la procedure reshycommandee doivent etre signalees Les tiges doivent etre tournees dun tour et demi tous les metres pour maintenir le trou droit et vertical et pour reduire le frottement lateral (voir seetian 7 Quand la profondeur depasse 10 m les tiges doivent etre tournees plus souvent pe tous les 02 metres Il est conseille dutiliser un dispositif de rotation mecanique quand la profondeur est importante

43

5 MFSURIS

Le nombre des coups doit etre nate tous les 01 metre pour DPL DPM et DPH (N ) et tous les 02 metre pour DPSH (N ) (voir seetian

10 9) Les coups peuvent facilement

20 etre mesures en marquant sur les tiges la profondeur de penetration definie 01 ou 02 m) Le domaine normal de coups - specialement aring legard de toute interpretation quantitative des resultats du sondage - se situe entre N = 3 et 50 pour DPL DPM et DPS et entre N = 5 et

10 20 100 pour DPSH Le rebondissement par coup doit etre inferieur aux 50 de la penetration par coup Dans des cas exceptionnels en-dehors de ces domaines) quand la resistance de penetration est faible pe dans des argiles molles (soft clays) la profondeur de peneshytration par coup peut etre enregistree Dans des sols dur ou la resistance de penetration est elevee la penetration peut etre notee pour un certain nombre de coups

Il est recommande de mesurer le couple necessaire pour la rotation du train de tiges pour pouvoir estimer le frottement lateral Le frottement latera l peut egalement etre mesure aring lai de dun manchon eaulissant aring l a proximi te de la pointe

La mesure de l a profondeur de penetration (partie conique de la pointe) doit etre effectuee aring + 2 cm

6 PRECAUTIONS COWfROLES ET VERIFICATIONS

Le mouton en chute libre (free-falling ) doit e tre monte lentement pour eviter que linertie du mouton ne le pousse au-dela de la hauteur definie Egalement le disposhysitif de prise (pick-up assembly) doit etre descendu lentement afin d eviter un impact significatif sur le mouton

Le defaut de rectitude des tiges des premiers 5 m aring

partir de la pointe ne doit pas exceder l mm de fleche sur une regle de l m Celui des tiges suivantes est limite aring 2 mm sur une regle de l m La longueur de la partie conique de la pointe ne peut etre pas diminuee p e par usure de plus de 10 du diametre de la longueur theorique de la partie conique de la pointe

La deviation maximale du dispositif dessai (test rig) est 2 l (horizontalement) sur 50 (verticalement)

La courbure et lexcentricite sant mesures dune maniere satisfaisante en solidarisant une tige avec une tige rectiligne et en maintenant cette derniere en centact avec une surface plane

7 CARACTERISTIQUES SPECIALES

Afin deviter le frottement lateral (skin friction) de la boue de forage peut etre injectee par des trous dans les parois des tiges aring proximite de la pointe Les trous doivent etre orientes horizontalement ou legerement vers le haut La pression de linjection doit etre suffisante pour que la boue de forage remplisse lespace annulaire entre sol et tige De meme un tubage peut etre utilise

Au lieu dun train de tiges creuses (diametre exterieur 22 mm) du DPL des tiges pleines (diametre exterieur = 20) mm sant utilisees

8 PRESENTATION DES RESULTATS DESSAI

Les informations suivantes doivent etre notees

a) Situation du sondage penetrometrique Type dinvestigation Date du sondage penetrometrique Numera du sondage

b) Numera du sondage et situation du sondage et du trou de forage (en cas de sondage de reference ) Poshysition de lappareillage dessai par rapport aring la surface du sol Cote et profondeur du niveau de la nappe

c ) Equipement utilise Type de penetrometre pointe tige tubage fluide de forage etc

d) Masse du mouton hauteur de chute et nombre de coups pour chaque penetration definie

e ) Profondeur aring laquelle les tiges sant soumises aring une rotation

f ) Modifications de la procedure normale telles que des interruptions ou des degats sur les tiges

g) Observations faites par loperateur telles que la nature du sol des bruits dans le train de tiges presence de pierres perturbations etc

Un exemple de feuille dessai est donne sur l a figure 2

F[Uill[HbullPRQJET

$1TUATIO PI Q JE

N OU SOIIOAGE OP[RATEURl COTES

SURFACE OU SOL NIPPEOUIFERE NIVEAUOEREF[ROumlKE

BUTD E L ESSAI l TYPE middot

[OUIP H[H T P(NiTROHirRE OYIIAHIOU(

IGE TUBAGE PQINTE fLUtOEOEFORAGE

PROFONOEURHI-OESSOUS HAUTEUR PlOMBREDE REHAROUE$ OUNIVEAU DE R(FERENCE OECHUTE COUSPOUR DHAI ROTATION BRUIT$MOUTON 02110 MOT IF OELARROumlfOR HE OETIGES

Fig 2 ExempLe de feuiLLe dessai pour La penetration dynamique

Les resultats du sondage penetrometrique doivent etre presentes selon des diagrammes qui donnent les valeurs N ou N en abscisses et la profondeuren ordonnees Un

10 20 exemple est presente sur la figure 3 Quand dautres mesures sont faites telle que la penetration pour en certain nombre de coups ces valeurs-la doivent etre transformees en valeurs N N ou rd qd avant

10 2 0 leur representation sur le diagramme Autrement il peut etre avantageux de transformer le nombre de coups par penetration definie en valeurs de resistance rd ou qd Les echelles de resistance doivent etre precisees en abscisses

44

Si le sondage etait mene selon le RTF la lettre R doit ~tre marquee sur la feuille dessai les graphiques etc suivis de abbreviation du type de penetrometre voir figure 3 Toutes modifications du RTF doit etre decrites completement sur les feuilles et les graphiques contenant les resultats de lessai

N0~1BRE DE COUPS POUR 01 m

OP L 10 20

E COTE OU TERRAIN NATUR EL 12 3 m NAP05rs

COTE DE LA NAPPE 103 m NAP er 1 o i3 TYPE DE PENETR OMETREo OPL D 15 z REFERE NCE OU PRO JET o ZW7 e 20 D DATE OU SONDAGEo 12-03 - BB er a 2 5 NU~IE RO OU SONDAGE 13

SITUAT lON XBOURG

Fig 3 Exemple de graphique de resultats d un sondage au penetrometre dynam i que l eger ( DPL )

9 DEVIATIONS PAR RAPPORT A L ESSAI DE REFERENCE

Quelques penetrometres legers ont des moutons d une masse de 20 kg (pe Bulgarian State Standard 8994-70 dautres pays utilisent des paintes dune surface aring la base de 5 cm 2 p e la Belgique German Standard DIN 4094 En Australie sent uti lises des penetrometres legers sans pointe pour des contrOles de qualite des sables compactes Quelques penetrometres moyens ont des moutons dune masse de 20 kg des hauteurs de chute de 20 cm sont utilises en dautres pays (pe DIN 4094 de la RFA et la Suisse) Est egalement utilisee une hauteur de chute de 50 cm pour quelques cas particuliers du DPSH (pe la Finlande) En France outre le DPSH le DPA du ISSMFE European Recommended Standard est egalement utilise comme essai de reference (Proc I Xth Intern Conf on Soil Mech and Found Eng Vol III p 110 Tokyo 1977 le diametre et la formede la pointe sont legerement differents

Quant au train de tiges du DPSH il est recommande daugmenter son diametre exterieur de 32 aring 36 mm (cette proposition est faite de la part de la France de lEspagne et de la Suede)

Avec DPL DPM et DPH les nombres des coups sont parfois comptes par intervalles de 02 m de profondeur de penetration Pour le DPSH on utilise parfois un intervalle de 03 m de profondeur de penetration

10 NOTIS EXPLICATIVIS ET COMMENTAIRFS

bull Note l

Les equations rd et qd sent

M g H

A e

M M g H

M + M A e

ou

rd et qd sont les valeurs de resistance en Pa kPa ou MPa

M est la masse du mouton M est la somme des masses du train de tiges de

lenclume et de la tige guide H est la hauteur de chute e est la penetration moyenne par coup A est la section de la base de pointe g est acceleration de la pesanteur

Les valeurs r - et qd sont des resistances conventionnel~es En particulier en cas de resistances elevee~ les diagamme~ rd et qd doivent etre analyses avec precaut1on

45

6 PRECAUTIONS CONTROLES ET VERIFICATIONS 9 3 Presentation des resultats

Un controle regulier de la verticalite des tiges doit La presentation des resultats de lessai de penetration etre realise specialement sur les 5 tiges inferieures par charges doit etre faite selon la forme montree aring la refpara 3 22 Fig 4

Une inspection reguliere de lusure de la pointe doit etre faite ref para 33 2

Lessai de penetration par charges ne doit pas etre effectue aring proximite dautres essais ou forages de fa~on generale la distance doit etre ~ 2 m

7 CALlERATION

Les poids doivent etre controles aring la livraison et marques

Le dynamometre doit etre calibre au moins une fois tous les 6 mois ou lorsque des changements etou des controles de routine sont effectues sur lappareil

8 SIWATIONS PARTICULIERES

Dans le but deviter que les tiges ne se fracturent par flechissement lorsque lessai est effectue dans leau un tube de forage doit etre utilise

9 RESULTATS

9 1 Resistance aring la penetration

911 Lorsque la resistance aring la penetration est inferieure aring l kN la charge normalisee necessaire pour donner une vitesse de penetration denviron 50 mmsee doit etre notee tout au long de lessai en fonction de l a profondeur (Fig 4) On doit noter sur le log du forage et sur les graphiques si lon a utilisedes poids ou un dynamometre (Voir Note 5 para 11)

9 12 Lorsque la resistance aring la penetration depasse l kN on doit noter le nombre de demi-tours necessaires pour chaque enfoncement de 02 m (Fig 4)

9 1 3 Lorsque le penetrometre doit etre fonce par battage (aring laide dun marteau ou des poids du penetrometre) on doit noter les profondeurs ainsi traversees

92 Remarques generales

9 21 Toutes les observations qui peuvent etre utiles lors de linterpretation des resultats doivent etre notees sur le log du sondage comme par exemple le diametre des tiges ainsi que les bruits et les vibrations dans les tiges quand la pointe traverse des sols non coherents (pierres graviers et sables) On doit aussi noter les interruptions dans le deroulement de lessai etc

9 22 Le type de materiel de rotation et la vitesse de rotation doivent etre notes sur le log de sondage

bull c route

z Preforaga ( tariere ~ 80)

~ 3 Q z o ~ s

7

o 1o 20 40 60

Charge kN dt02 m

WST 22 ssai de penetration par charges tiges de 22 mm

dt02 m Noabre de demi-tours pour 20 cm denfoncement

croute croute dargile dessechee Preforaga Pretorage juaqul ce niveau avec une

(tariere 11 80) tariere de 80 mm de diametra

Le diagramme de droite indique les charges appliquees

Fig 4 ExempLe de presentation des resuLtats d un essai de penetration par charges (WST ) reaLise avec des tiges de 22 mm

10 ECART DU MODE OPERATOIRE DE REFERENCE

Tout ecart du Mode Operatoire de Reference de lEssai de Penetration doit etre explicitement decrit dans le rapport d essai

Le diametre des tiges doit etre note puisqu il peut avoi r une influence majeure sur les resultats de lessai

11 NOTES EXPLICATIVES

bull Note l paragraphe 321

Les tiges et les raccords doivent etre fabriques en acier aring haute resistance Il doit etre considere que des tiges de 25 mm peuvent donner une resistance totale plus grande que des tiges de 22 mm specialement dans les sols coherents

bull Note 2 paragraphe 423

Des differences entre les essais manuels et mecaniques se produisent parfois Lorsque de telles differences sont susceptibles de se produire comme cest le cas pour lestimation des densites relatives des sols laumlches sans cohesion il faut faire des comparaisons entre des essais manuels et des essais mecaniques Generalement la resistance de penetration en rotation obtenue lorsque l e penetrometre est opere mecaniquement est plus grande que celle provenant de lessai manuel

48

bull Note 3 paragraphe 431

Dans le cas ou le frottement lateral le long de la partie superieure du train de tiges peut influencer les resultats de facon significative on doit comparer les resultats a ceux dun essai execute dans un preforage Le preforage est generalement necessaire dans les croutes dessechees et dans les remblais Lorsque la difference de resistance est grande entre les deux essais il faut realiser des preforages pour tous les essais du site Le preforage doit etre effectue a laide dune tarriere dau moins 50 mm de diametre Pour estimer lepaisseur de la couche durcie on fait un essai de penetration aring partir de la surface du sol

bull Note 4 paragraphe 432

On terminera un essai de penetration jusquau substratum rigide en frappant sur le train de tiges aring laide dun marteau ou en laissant tomber quelques poids sur le collier pour verifier que le refus nest pas temporaire Sil est possible de traverser la couche dure lessai doit etre poursuivi

On fait parfois suivre lessai de penetration par charges dun forage par percussion jusquaring une plus grande profondeur afin de determiner par exemple aring quelle profondeur des pieux doivent etre fonces

bull Note 5 paragraphe 911

Dans les sols mous quand la resistance aring la penetration est inferieure aring l kN on peut utiliser un dynamometre aring la place des poids Dans ce cas la charge enregistree doit etre rattachee aring la charge normalisee la plus proche et notee de facon semblable

49

The Swedish Geotechnical Institute is a governshyment agency deal i ng with geotechnical research information and consultancy The purpose of the Institute is to achieve better techniques safety and economy by the correct application of geotechnical knowledge in the building process

Research Development of techniques for soil improvement and foundation engineering Environmental and energy geotechnics Design and developmerit of field and laboratory equipment

Information Research reports brochures courses Running the Swedish central geotechnical literature service Computerized retrieval system

Consultancy Design advice and recommendations including site investigations field and laboratory measureshyments Technical expert in the event of disputes

STATENS GEOTEKNISKA INSTITUT SWEDISH GEOTECHNICAL INSTITUTE

S-581 01 Linkoumlping Sweden Tel 013-115100 lnt +4613115100

Telex 50125 (VTISGI S) Telefax 013-131696 lnt +4613131696

Si le sondage etait mene selon le RTF la lettre R doit ~tre marquee sur la feuille dessai les graphiques etc suivis de abbreviation du type de penetrometre voir figure 3 Toutes modifications du RTF doit etre decrites completement sur les feuilles et les graphiques contenant les resultats de lessai

N0~1BRE DE COUPS POUR 01 m

OP L 10 20

E COTE OU TERRAIN NATUR EL 12 3 m NAP05rs

COTE DE LA NAPPE 103 m NAP er 1 o i3 TYPE DE PENETR OMETREo OPL D 15 z REFERE NCE OU PRO JET o ZW7 e 20 D DATE OU SONDAGEo 12-03 - BB er a 2 5 NU~IE RO OU SONDAGE 13

SITUAT lON XBOURG

Fig 3 Exemple de graphique de resultats d un sondage au penetrometre dynam i que l eger ( DPL )

9 DEVIATIONS PAR RAPPORT A L ESSAI DE REFERENCE

Quelques penetrometres legers ont des moutons d une masse de 20 kg (pe Bulgarian State Standard 8994-70 dautres pays utilisent des paintes dune surface aring la base de 5 cm 2 p e la Belgique German Standard DIN 4094 En Australie sent uti lises des penetrometres legers sans pointe pour des contrOles de qualite des sables compactes Quelques penetrometres moyens ont des moutons dune masse de 20 kg des hauteurs de chute de 20 cm sont utilises en dautres pays (pe DIN 4094 de la RFA et la Suisse) Est egalement utilisee une hauteur de chute de 50 cm pour quelques cas particuliers du DPSH (pe la Finlande) En France outre le DPSH le DPA du ISSMFE European Recommended Standard est egalement utilise comme essai de reference (Proc I Xth Intern Conf on Soil Mech and Found Eng Vol III p 110 Tokyo 1977 le diametre et la formede la pointe sont legerement differents

Quant au train de tiges du DPSH il est recommande daugmenter son diametre exterieur de 32 aring 36 mm (cette proposition est faite de la part de la France de lEspagne et de la Suede)

Avec DPL DPM et DPH les nombres des coups sont parfois comptes par intervalles de 02 m de profondeur de penetration Pour le DPSH on utilise parfois un intervalle de 03 m de profondeur de penetration

10 NOTIS EXPLICATIVIS ET COMMENTAIRFS

bull Note l

Les equations rd et qd sent

M g H

A e

M M g H

M + M A e

ou

rd et qd sont les valeurs de resistance en Pa kPa ou MPa

M est la masse du mouton M est la somme des masses du train de tiges de

lenclume et de la tige guide H est la hauteur de chute e est la penetration moyenne par coup A est la section de la base de pointe g est acceleration de la pesanteur

Les valeurs r - et qd sont des resistances conventionnel~es En particulier en cas de resistances elevee~ les diagamme~ rd et qd doivent etre analyses avec precaut1on

45

6 PRECAUTIONS CONTROLES ET VERIFICATIONS 9 3 Presentation des resultats

Un controle regulier de la verticalite des tiges doit La presentation des resultats de lessai de penetration etre realise specialement sur les 5 tiges inferieures par charges doit etre faite selon la forme montree aring la refpara 3 22 Fig 4

Une inspection reguliere de lusure de la pointe doit etre faite ref para 33 2

Lessai de penetration par charges ne doit pas etre effectue aring proximite dautres essais ou forages de fa~on generale la distance doit etre ~ 2 m

7 CALlERATION

Les poids doivent etre controles aring la livraison et marques

Le dynamometre doit etre calibre au moins une fois tous les 6 mois ou lorsque des changements etou des controles de routine sont effectues sur lappareil

8 SIWATIONS PARTICULIERES

Dans le but deviter que les tiges ne se fracturent par flechissement lorsque lessai est effectue dans leau un tube de forage doit etre utilise

9 RESULTATS

9 1 Resistance aring la penetration

911 Lorsque la resistance aring la penetration est inferieure aring l kN la charge normalisee necessaire pour donner une vitesse de penetration denviron 50 mmsee doit etre notee tout au long de lessai en fonction de l a profondeur (Fig 4) On doit noter sur le log du forage et sur les graphiques si lon a utilisedes poids ou un dynamometre (Voir Note 5 para 11)

9 12 Lorsque la resistance aring la penetration depasse l kN on doit noter le nombre de demi-tours necessaires pour chaque enfoncement de 02 m (Fig 4)

9 1 3 Lorsque le penetrometre doit etre fonce par battage (aring laide dun marteau ou des poids du penetrometre) on doit noter les profondeurs ainsi traversees

92 Remarques generales

9 21 Toutes les observations qui peuvent etre utiles lors de linterpretation des resultats doivent etre notees sur le log du sondage comme par exemple le diametre des tiges ainsi que les bruits et les vibrations dans les tiges quand la pointe traverse des sols non coherents (pierres graviers et sables) On doit aussi noter les interruptions dans le deroulement de lessai etc

9 22 Le type de materiel de rotation et la vitesse de rotation doivent etre notes sur le log de sondage

bull c route

z Preforaga ( tariere ~ 80)

~ 3 Q z o ~ s

7

o 1o 20 40 60

Charge kN dt02 m

WST 22 ssai de penetration par charges tiges de 22 mm

dt02 m Noabre de demi-tours pour 20 cm denfoncement

croute croute dargile dessechee Preforaga Pretorage juaqul ce niveau avec une

(tariere 11 80) tariere de 80 mm de diametra

Le diagramme de droite indique les charges appliquees

Fig 4 ExempLe de presentation des resuLtats d un essai de penetration par charges (WST ) reaLise avec des tiges de 22 mm

10 ECART DU MODE OPERATOIRE DE REFERENCE

Tout ecart du Mode Operatoire de Reference de lEssai de Penetration doit etre explicitement decrit dans le rapport d essai

Le diametre des tiges doit etre note puisqu il peut avoi r une influence majeure sur les resultats de lessai

11 NOTES EXPLICATIVES

bull Note l paragraphe 321

Les tiges et les raccords doivent etre fabriques en acier aring haute resistance Il doit etre considere que des tiges de 25 mm peuvent donner une resistance totale plus grande que des tiges de 22 mm specialement dans les sols coherents

bull Note 2 paragraphe 423

Des differences entre les essais manuels et mecaniques se produisent parfois Lorsque de telles differences sont susceptibles de se produire comme cest le cas pour lestimation des densites relatives des sols laumlches sans cohesion il faut faire des comparaisons entre des essais manuels et des essais mecaniques Generalement la resistance de penetration en rotation obtenue lorsque l e penetrometre est opere mecaniquement est plus grande que celle provenant de lessai manuel

48

bull Note 3 paragraphe 431

Dans le cas ou le frottement lateral le long de la partie superieure du train de tiges peut influencer les resultats de facon significative on doit comparer les resultats a ceux dun essai execute dans un preforage Le preforage est generalement necessaire dans les croutes dessechees et dans les remblais Lorsque la difference de resistance est grande entre les deux essais il faut realiser des preforages pour tous les essais du site Le preforage doit etre effectue a laide dune tarriere dau moins 50 mm de diametre Pour estimer lepaisseur de la couche durcie on fait un essai de penetration aring partir de la surface du sol

bull Note 4 paragraphe 432

On terminera un essai de penetration jusquau substratum rigide en frappant sur le train de tiges aring laide dun marteau ou en laissant tomber quelques poids sur le collier pour verifier que le refus nest pas temporaire Sil est possible de traverser la couche dure lessai doit etre poursuivi

On fait parfois suivre lessai de penetration par charges dun forage par percussion jusquaring une plus grande profondeur afin de determiner par exemple aring quelle profondeur des pieux doivent etre fonces

bull Note 5 paragraphe 911

Dans les sols mous quand la resistance aring la penetration est inferieure aring l kN on peut utiliser un dynamometre aring la place des poids Dans ce cas la charge enregistree doit etre rattachee aring la charge normalisee la plus proche et notee de facon semblable

49

The Swedish Geotechnical Institute is a governshyment agency deal i ng with geotechnical research information and consultancy The purpose of the Institute is to achieve better techniques safety and economy by the correct application of geotechnical knowledge in the building process

Research Development of techniques for soil improvement and foundation engineering Environmental and energy geotechnics Design and developmerit of field and laboratory equipment

Information Research reports brochures courses Running the Swedish central geotechnical literature service Computerized retrieval system

Consultancy Design advice and recommendations including site investigations field and laboratory measureshyments Technical expert in the event of disputes

STATENS GEOTEKNISKA INSTITUT SWEDISH GEOTECHNICAL INSTITUTE

S-581 01 Linkoumlping Sweden Tel 013-115100 lnt +4613115100

Telex 50125 (VTISGI S) Telefax 013-131696 lnt +4613131696

6 PRECAUTIONS CONTROLES ET VERIFICATIONS 9 3 Presentation des resultats

Un controle regulier de la verticalite des tiges doit La presentation des resultats de lessai de penetration etre realise specialement sur les 5 tiges inferieures par charges doit etre faite selon la forme montree aring la refpara 3 22 Fig 4

Une inspection reguliere de lusure de la pointe doit etre faite ref para 33 2

Lessai de penetration par charges ne doit pas etre effectue aring proximite dautres essais ou forages de fa~on generale la distance doit etre ~ 2 m

7 CALlERATION

Les poids doivent etre controles aring la livraison et marques

Le dynamometre doit etre calibre au moins une fois tous les 6 mois ou lorsque des changements etou des controles de routine sont effectues sur lappareil

8 SIWATIONS PARTICULIERES

Dans le but deviter que les tiges ne se fracturent par flechissement lorsque lessai est effectue dans leau un tube de forage doit etre utilise

9 RESULTATS

9 1 Resistance aring la penetration

911 Lorsque la resistance aring la penetration est inferieure aring l kN la charge normalisee necessaire pour donner une vitesse de penetration denviron 50 mmsee doit etre notee tout au long de lessai en fonction de l a profondeur (Fig 4) On doit noter sur le log du forage et sur les graphiques si lon a utilisedes poids ou un dynamometre (Voir Note 5 para 11)

9 12 Lorsque la resistance aring la penetration depasse l kN on doit noter le nombre de demi-tours necessaires pour chaque enfoncement de 02 m (Fig 4)

9 1 3 Lorsque le penetrometre doit etre fonce par battage (aring laide dun marteau ou des poids du penetrometre) on doit noter les profondeurs ainsi traversees

92 Remarques generales

9 21 Toutes les observations qui peuvent etre utiles lors de linterpretation des resultats doivent etre notees sur le log du sondage comme par exemple le diametre des tiges ainsi que les bruits et les vibrations dans les tiges quand la pointe traverse des sols non coherents (pierres graviers et sables) On doit aussi noter les interruptions dans le deroulement de lessai etc

9 22 Le type de materiel de rotation et la vitesse de rotation doivent etre notes sur le log de sondage

bull c route

z Preforaga ( tariere ~ 80)

~ 3 Q z o ~ s

7

o 1o 20 40 60

Charge kN dt02 m

WST 22 ssai de penetration par charges tiges de 22 mm

dt02 m Noabre de demi-tours pour 20 cm denfoncement

croute croute dargile dessechee Preforaga Pretorage juaqul ce niveau avec une

(tariere 11 80) tariere de 80 mm de diametra

Le diagramme de droite indique les charges appliquees

Fig 4 ExempLe de presentation des resuLtats d un essai de penetration par charges (WST ) reaLise avec des tiges de 22 mm

10 ECART DU MODE OPERATOIRE DE REFERENCE

Tout ecart du Mode Operatoire de Reference de lEssai de Penetration doit etre explicitement decrit dans le rapport d essai

Le diametre des tiges doit etre note puisqu il peut avoi r une influence majeure sur les resultats de lessai

11 NOTES EXPLICATIVES

bull Note l paragraphe 321

Les tiges et les raccords doivent etre fabriques en acier aring haute resistance Il doit etre considere que des tiges de 25 mm peuvent donner une resistance totale plus grande que des tiges de 22 mm specialement dans les sols coherents

bull Note 2 paragraphe 423

Des differences entre les essais manuels et mecaniques se produisent parfois Lorsque de telles differences sont susceptibles de se produire comme cest le cas pour lestimation des densites relatives des sols laumlches sans cohesion il faut faire des comparaisons entre des essais manuels et des essais mecaniques Generalement la resistance de penetration en rotation obtenue lorsque l e penetrometre est opere mecaniquement est plus grande que celle provenant de lessai manuel

48

bull Note 3 paragraphe 431

Dans le cas ou le frottement lateral le long de la partie superieure du train de tiges peut influencer les resultats de facon significative on doit comparer les resultats a ceux dun essai execute dans un preforage Le preforage est generalement necessaire dans les croutes dessechees et dans les remblais Lorsque la difference de resistance est grande entre les deux essais il faut realiser des preforages pour tous les essais du site Le preforage doit etre effectue a laide dune tarriere dau moins 50 mm de diametre Pour estimer lepaisseur de la couche durcie on fait un essai de penetration aring partir de la surface du sol

bull Note 4 paragraphe 432

On terminera un essai de penetration jusquau substratum rigide en frappant sur le train de tiges aring laide dun marteau ou en laissant tomber quelques poids sur le collier pour verifier que le refus nest pas temporaire Sil est possible de traverser la couche dure lessai doit etre poursuivi

On fait parfois suivre lessai de penetration par charges dun forage par percussion jusquaring une plus grande profondeur afin de determiner par exemple aring quelle profondeur des pieux doivent etre fonces

bull Note 5 paragraphe 911

Dans les sols mous quand la resistance aring la penetration est inferieure aring l kN on peut utiliser un dynamometre aring la place des poids Dans ce cas la charge enregistree doit etre rattachee aring la charge normalisee la plus proche et notee de facon semblable

49

The Swedish Geotechnical Institute is a governshyment agency deal i ng with geotechnical research information and consultancy The purpose of the Institute is to achieve better techniques safety and economy by the correct application of geotechnical knowledge in the building process

Research Development of techniques for soil improvement and foundation engineering Environmental and energy geotechnics Design and developmerit of field and laboratory equipment

Information Research reports brochures courses Running the Swedish central geotechnical literature service Computerized retrieval system

Consultancy Design advice and recommendations including site investigations field and laboratory measureshyments Technical expert in the event of disputes

STATENS GEOTEKNISKA INSTITUT SWEDISH GEOTECHNICAL INSTITUTE

S-581 01 Linkoumlping Sweden Tel 013-115100 lnt +4613115100

Telex 50125 (VTISGI S) Telefax 013-131696 lnt +4613131696

bull Note 3 paragraphe 431

Dans le cas ou le frottement lateral le long de la partie superieure du train de tiges peut influencer les resultats de facon significative on doit comparer les resultats a ceux dun essai execute dans un preforage Le preforage est generalement necessaire dans les croutes dessechees et dans les remblais Lorsque la difference de resistance est grande entre les deux essais il faut realiser des preforages pour tous les essais du site Le preforage doit etre effectue a laide dune tarriere dau moins 50 mm de diametre Pour estimer lepaisseur de la couche durcie on fait un essai de penetration aring partir de la surface du sol

bull Note 4 paragraphe 432

On terminera un essai de penetration jusquau substratum rigide en frappant sur le train de tiges aring laide dun marteau ou en laissant tomber quelques poids sur le collier pour verifier que le refus nest pas temporaire Sil est possible de traverser la couche dure lessai doit etre poursuivi

On fait parfois suivre lessai de penetration par charges dun forage par percussion jusquaring une plus grande profondeur afin de determiner par exemple aring quelle profondeur des pieux doivent etre fonces

bull Note 5 paragraphe 911

Dans les sols mous quand la resistance aring la penetration est inferieure aring l kN on peut utiliser un dynamometre aring la place des poids Dans ce cas la charge enregistree doit etre rattachee aring la charge normalisee la plus proche et notee de facon semblable

49

The Swedish Geotechnical Institute is a governshyment agency deal i ng with geotechnical research information and consultancy The purpose of the Institute is to achieve better techniques safety and economy by the correct application of geotechnical knowledge in the building process

Research Development of techniques for soil improvement and foundation engineering Environmental and energy geotechnics Design and developmerit of field and laboratory equipment

Information Research reports brochures courses Running the Swedish central geotechnical literature service Computerized retrieval system

Consultancy Design advice and recommendations including site investigations field and laboratory measureshyments Technical expert in the event of disputes

STATENS GEOTEKNISKA INSTITUT SWEDISH GEOTECHNICAL INSTITUTE

S-581 01 Linkoumlping Sweden Tel 013-115100 lnt +4613115100

Telex 50125 (VTISGI S) Telefax 013-131696 lnt +4613131696

The Swedish Geotechnical Institute is a governshyment agency deal i ng with geotechnical research information and consultancy The purpose of the Institute is to achieve better techniques safety and economy by the correct application of geotechnical knowledge in the building process

Research Development of techniques for soil improvement and foundation engineering Environmental and energy geotechnics Design and developmerit of field and laboratory equipment

Information Research reports brochures courses Running the Swedish central geotechnical literature service Computerized retrieval system

Consultancy Design advice and recommendations including site investigations field and laboratory measureshyments Technical expert in the event of disputes

STATENS GEOTEKNISKA INSTITUT SWEDISH GEOTECHNICAL INSTITUTE

S-581 01 Linkoumlping Sweden Tel 013-115100 lnt +4613115100

Telex 50125 (VTISGI S) Telefax 013-131696 lnt +4613131696