Interactive Design – The Role of Geotechnical Instruments · PDF fileInteractive Design – The Role of Geotechnical Instruments ... drains and dynamic compaction. ... FLAC (Version

UNIVERSITYOF ZAGREB

17th European Young Geotechnical Engineer's Conference (EYGEC) 2006Zagreb 20-22 July 2006

Interactive Design Interactive Design –– The Role of The Role of Geotechnical InstrumentsGeotechnical Instruments

MehoMeho--SaSašša Kovaa Kovaččevievićć

University of ZagrebUniversity of ZagrebFaculty of Civil EngineeringFaculty of Civil Engineering

UNIVERSITYOF ZAGREBOverviewOverview

Interactive geotechnical designInteractive geotechnical design

Monitoring instrumentsMonitoring instruments

Case studiesCase studiesAnchored diaphragm wallsAnchored diaphragm wallsReinforced Soil StructuresReinforced Soil StructuresPile FoundationsPile FoundationsTunnel ExcavationsTunnel ExcavationsDeep ExcavationsDeep Excavations

Addition to the interactive desingAddition to the interactive desing

ConclusionsConclusions

UNIVERSITYOF ZAGREBInteractive geotechnical designInteractive geotechnical design

Geotechnical design has to deal with limited Geotechnical design has to deal with limited knowledge of ground conditions which introduces knowledge of ground conditions which introduces uncertainties and in turn design conservatism;uncertainties and in turn design conservatism;

Observations during construction may reduce Observations during construction may reduce uncertainties; if design can be adjusted accordingly, uncertainties; if design can be adjusted accordingly, conservatism may be reduceconservatism may be reducedd and economy may and economy may benefit;benefit;

UNIVERSITYOF ZAGREBInteractive geotechnical designInteractive geotechnical design

Geotechnical design approaches:Geotechnical design approaches:

••Conventional approach Conventional approach -- ““learnlearn--thenthen--gogo””–– Finalized prior to construction; Observations during Finalized prior to construction; Observations during

construction lost for optimization; Conservative construction lost for optimization; Conservative design design ““coveringcovering”” uncertainties;uncertainties;

••Interactive designInteractive design -- ““learnlearn--asas--youyou--gogo””–– Advanced into the construction process utilizing Advanced into the construction process utilizing

observations during construction for optimization; observations during construction for optimization; conservatism may be reduced.conservatism may be reduced.

UNIVERSITYOF ZAGREBMonitoring instrumentsMonitoring instruments

Eurocode 7 states the following requirements for Eurocode 7 states the following requirements for monitoring:monitoring:••““...a plan of monitoring shall be devised which will ...a plan of monitoring shall be devised which will reveal whether the actual behaviour lies within reveal whether the actual behaviour lies within acceptable limits. The monitoring shall make this acceptable limits. The monitoring shall make this clear at a sufficiently early stage; and with sufficiently clear at a sufficiently early stage; and with sufficiently short intervals to allow contingency actions to be short intervals to allow contingency actions to be undertaken successfully. The response time of the undertaken successfully. The response time of the instruments and procedures for analysing the results instruments and procedures for analysing the results shall be sufficiently rapid in relation to the possible shall be sufficiently rapid in relation to the possible evolution of the system...evolution of the system...””


The most commonly used instrumentsThe most commonly used instrumentsin geotechnical monitoring in geotechnical monitoring areare::

SSurveying instrumentsurveying instrumentsCClinometers linometers and Tiltmetersand TiltmetersInclinometersInclinometers, E, Extensometers,xtensometers,SSliding deformeters, liding deformeters, SSliding micrometersliding micrometersMeasuring anchorsMeasuring anchorsLLoad cellsoad cellsPPressure cellsressure cellsStrain gaugesStrain gaugesPPiezometersiezometers etc.etc.


Surveying instrumentsSurveying instruments3D displacements of ground and geotechnical 3D displacements of ground and geotechnical structuresstructures

Accuracy: 1 mmAccuracy: 1 mm

Typical Applications:Typical Applications:Monitoring magnitude and rate ofMonitoring magnitude and rate ofhorizontal and vertical deformations ofhorizontal and vertical deformations ofground surface and structuresground surface and structures

Monitoring deformation due to nearbyMonitoring deformation due to nearbyconstruction activity or to slope movementsconstruction activity or to slope movements

Monitoring deformation in tunnels under Monitoring deformation in tunnels under construction to ensure safety and to verify thatconstruction to ensure safety and to verify thatactual performance conforms to predictionsactual performance conforms to predictions


CClinometerlinometerChange in rotation of points on or in the Change in rotation of points on or in the ground or a structureground or a structure

Accuracy: 0,003 mm/m Accuracy: 0,003 mm/m

Typical Applications:Typical Applications:Monitoring rotation caused by mining,Monitoring rotation caused by mining,tunneling, soil compaction or excavationtunneling, soil compaction or excavation

Monitoring rotation and deflectionMonitoring rotation and deflectionof concrete dams, bridges orof concrete dams, bridges orretaining wallsretaining walls

Monitoring rotation of existing buildingsMonitoring rotation of existing buildingsclosely surrounded the construction siteclosely surrounded the construction site


InclinometerInclinometerLateral deformations along the boreholeLateral deformations along the borehole

Accuracy: 0,1 mm/m Accuracy: 0,1 mm/m

Typical Applications:Typical Applications:Determination of potential slip surfacesDetermination of potential slip surfaces

Monitoring lateral movements inMonitoring lateral movements inembankments and landslide areasembankments and landslide areas

Monitoring deflections of retainingMonitoring deflections of retainingwalls and pileswalls and piles

Monitoring deformations of excavationMonitoring deformations of excavationwalls, tunnels and shaftswalls, tunnels and shafts


SSliding deformeterliding deformeter andandSSliding micrometer liding micrometer Longitudinal deformations along the boreholeLongitudinal deformations along the borehole

Accuracy: 0,03 mm/m to 0,003 mm/mAccuracy: 0,03 mm/m to 0,003 mm/m

Typical Applications:Typical Applications:Determination of potential slip surfacesDetermination of potential slip surfaces

Monitoring strain development Monitoring strain development in tunnels and underground openingsin tunnels and underground openings

Monitoring strain profiles in dams,Monitoring strain profiles in dams,embankments, excavations etc.embankments, excavations etc.

Monitoring settlement in foundationsMonitoring settlement in foundations


Measuring anchors Measuring anchors

Deformations along the anchorDeformations along the anchor

Combination of an anchor or rock bolt Combination of an anchor or rock bolt and an extensometer.and an extensometer.

Accuracy: 0,01 mm Accuracy: 0,01 mm

Typical Applications:Typical Applications:Determination of te optimal anchor Determination of te optimal anchor lengthlength

Underground cavities where theUnderground cavities where theformation of rock supporting ring isformation of rock supporting ring isintended by system anchoringintended by system anchoring

Control of the anchor body in theControl of the anchor body in theindividual depth rangesindividual depth ranges


LLoad cellsoad cells

Load in foundation anchors or rock bolts, Load in foundation anchors or rock bolts, tunnel excavation support or static pile tunnel excavation support or static pile teststests

Nominal load: 250 to 2500 kNNominal load: 250 to 2500 kNAccuracy: 0,5% of FS Accuracy: 0,5% of FS

Typical Applications:Typical Applications:Performance monitoring in Performance monitoring in underground constructionunderground construction

Retaining walls and excavation supportRetaining walls and excavation support

Slope engineeringSlope engineering

Pile load and pile load testsPile load and pile load tests


PPressure cellsressure cells

Stress changes in concrete, soil and fills, contact joints and in boreholes

Nominal pressure: 2 to 200 barsNominal pressure: 2 to 200 barsAccuracy: 0,25% of FS Accuracy: 0,25% of FS

Typical Applications:Typical Applications:Radial and tangential pressure in Radial and tangential pressure in tunnelstunnels

Earth and foundation pressure inEarth and foundation pressure infoundation engineeringfoundation engineering

Secondary stress state in geomechanicsSecondary stress state in geomechanics

Total soil pressures in landfills and damsTotal soil pressures in landfills and dams


Strain gaugesStrain gaugesStrain in steel, reinforced concrete and mass concrete

Accuracy: 1 microstrain Accuracy: 1 microstrain

Typical Applications:Typical Applications:Mesuring strain in tunnel linings andMesuring strain in tunnel linings andsupportssupports

Monitoring structural members ofMonitoring structural members ofbuildings and bridges during and afterbuildings and bridges during and afterconstructionconstruction

Monitorig load in strutting systems forMonitorig load in strutting systems fordeep excavationsdeep excavations

Determining load changes on groundDetermining load changes on groundanchors or rock boltsanchors or rock bolts


PiezometersPiezometersPore water pressures

Standpipe, Pneumatic, VW piezometersStandpipe, Pneumatic, VW piezometers

Nominal pressure: 2 to 40 barsNominal pressure: 2 to 40 barsAccuracy: 0,1 % of FS Accuracy: 0,1 % of FS

Typical Applications:Typical Applications:Determine the stability of natural slopes, Determine the stability of natural slopes,

embankments and damsembankments and dams

Determine safe rates of fill and Determine safe rates of fill and excavationexcavation

Monitoring the effects of dewatering Monitoring the effects of dewatering systems used for excavationssystems used for excavations

Monitoring ground improvement Monitoring ground improvement technics such as vertical drains, sand technics such as vertical drains, sand drains and dynamic compactiondrains and dynamic compaction

UNIVERSITYOF ZAGREB

Anchored diaphragm wallAnchored diaphragm wall

fill

firm clay

0-2

-10

-15

depth, m 0.8

gravel

stiff clay -18

-23

freelengthgrouted

length

prestressedanchor

±0 elevation 119.6 m

Diaphragm wallwith inclinometers

UNIVERSITYOF ZAGREBAnchored diaphragm wallAnchored diaphragm wall

0 1 2 3Displacement (cm)

0

5

10

15

20

25D

epth

(m)

predicted

measured

Stage 2

Stage 4

Stage 7

FLAC (Version 3.40)

LEGEND

29-Mar-99 14:45 step 12678 -3.911E+01 <x< 2.311E+01 -2.561E+01 <y< 3.661E+01

Boundary plot

0 1E 1

Displacement vectorsMax Vector = 3.063E-02

0 1E -1

Beam plotCable plot

-2.000

-1.000

0.000

1.000

2.000

3.000

(*10^1)

-3.000 -2.000 -1.000 0.000 1.000 2.000(*10^1)

JOB TITLE : DIJAFRAGMA, IBLEROV TRG, FAZA 7

University of Zagreb Faculty of Civil Engineering

UNIVERSITYOF ZAGREB

Reinforced soil structureReinforced soil structure

5 m

D-1 0+0,00 m

0+3,05 m

0+8,55 m

deformeter D-1readings

D-2D-2

D-3D-3

+10.50

+3.62

+17.21

+24.30

23.97 m

2.75

: 1

2.75

: 1

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Krapincica viaductKrapincica viaduct

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Jet grouted columns

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sliding micrometer

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Bridge

pier Load (kN)

Pile cup construction (%)

Pile base (%)

Skin friction (%)

S3D 11724 34 21 45 S3L 11724 25 31 43 S4D 11821 33 20 47 S4L 11821 33 28 39

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

0200040006000800010000

Dep

th (

m)

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

02004006008001000

Dep

th (

m)

Longitudinal force (kN) Pile skin friction (kN/m')

pile cup construction pile cup construction

pile basepile base

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St MarkSt Mark’’s tunnel excavations tunnel excavation

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settlem ent 1 cm

1 2 3 4 5 6 7

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UNIVERSITYOF ZAGREBZagrad excavationZagrad excavation

POMERIO ST. No.19INCLINOMETER -VERTICAL

30

0L=16.0 m

50Horizontal distance (m)

1510 2520

L=12.0 m

Ele

vatio

n (m

)

15 Horizontal deformeterL=16.0 m

5

10

L=16.0 m20

25

DEFORMETER

POMERIO ST.

3530

SELF-DRILLING ROCKBOLTS

SELF-DRILLING ROCKBOLTS SELF-DRILLING ROCKBOLTS

UNIVERSITYOF ZAGREBKaufland excavationKaufland excavation

0

68

74

70

72

76

80

78

82

84

86

90

88

92

V - vertical inclinometer - deformeter L=18.00 mH - horizontal deformeter L=15.00 m

SELF-DRILLING ROCKBOLTSL=6.00 m

+75.30 terrace level

+73.30 foundation level

10 20 30

H

V

40



L=12.00 m

L=9.00 m

+84.50

CRNCIC ST.

Slope linebefore excavation

BUILDING

Horizontal distance (m)

Elev

atio

n (m

)

UNIVERSITYOF ZAGREBLenac excavationLenac excavation

Horizontal deformeterL=15.00 m

DEFORMETER L=40.0 m

25 20 10 5 040 35 30Horizontal distance (m)

Elev

atio

n (m

)

SELF-DRILLING

L=12.00 m

ROCKBOLTSL=9.00 m

ROCKBOLTSL=6.00 m

3540

3025

010

205

45

ROCKBOLTS

VERTICAL INCLINOMETER -

UNIVERSITYOF ZAGREBWTC excavationWTC excavation

45

3735

4139

43

47

5149

5553

0 10 20 30

V

H

V - vertical inclinometer - deformeter L=16.00 mH - horizontal deformeter L=15.00 m

ROCKBOLTSL=9.00 m

ROCKBOLTSL=6.00 m

ROCKBOLTSL=5.00 m

Ele

vatio

n (m

)

Horizontal distance (m)

SELF-DRILLING

SELF-DRILLING

UNIVERSITYOF ZAGREBAcoustic emissionAcoustic emission




0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 20000 40000 60000 80000 100000 120000 140000

Number of counts/tensile force (n/kN)

Tens

ilefo

rce

(kN

)

1

4

7

10

13

16

19

22

25

28

31

34

37

40

43

46

UNIVERSITYOF ZAGREBConclusionsConclusions

1. 1. The The Interactive geotechnical designInteractive geotechnical design is a is a powerful design tool.powerful design tool. A rational design, which A rational design, which makes provisions for geotechnical monitoring, makes provisions for geotechnical monitoring, can provide a substantial improvement in can provide a substantial improvement in geotechnical construction both in terms of geotechnical construction both in terms of safety and saving.safety and saving.

2. 2. Another great advantage of monitoring is in the Another great advantage of monitoring is in the gathering of very valuable information on in gathering of very valuable information on in situ soil and rock behaviour during situ soil and rock behaviour during construction works.construction works.

UNIVERSITYOF ZAGREBConclusionsConclusions

3. S3. Sophisticated nonlinear constitutive models can ophisticated nonlinear constitutive models can be used with data bases provided by be used with data bases provided by geotechnical measurements.geotechnical measurements.

4. Back analyses can substantially improve our 4. Back analyses can substantially improve our knowledge on soil parameters and soil knowledge on soil parameters and soil behaviour in general.behaviour in general.

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Thank you for your attentionThank you for your attention

Documents

Interactive Design – The Role of Geotechnical Instruments · PDF fileInteractive Design – The Role of Geotechnical Instruments ... drains and dynamic compaction. ... FLAC (Version