Advance Soil Mechanics

Advance Soil mechanicsAdvance Soil mechanicsPresent by Mr. Sieng Present by Mr. Sieng

PEOUPEOUMaster science of Master science of

geotechnical engineeringgeotechnical engineering

Soils particle sizeSoils particle size

1 9 .5 m m > d > 4 .7 6m m.

G rav e l

4 .76 m m >d > 0 .07 5m m

S and

C oa rse g ra in ed so i ls

0 .07 5 m m > d> 0 .0 0 2m m

S ilt

d <0 .00 2m m

C lay

F ine g ra in ed so i ls

S o i ls

Sieve analysis Sieve analysis methodmethod

For coarse For coarse grained grained

soilssoils

Retained cumulativeRetained cumulative

%R=%R= %100.

..

weighttotalcumulativeretainedweight

Passing cumulative

%P = 100-%R

Logarithm scaleLogarithm scale

Logd

0.001 0.01 0.1 1 10 100

a

If 0.001<d<0.01

X=a.Log(1000d)

If 0.01<d<0.1

X=a.Log(100d)

If 0.1<d<1

X=a.Log(10d)

If 1<d<10

X=a.Log(d)

If 10<d<100

X=a.Log(0.1d)

HydrometHydrometer analysiser analysis

For fine For fine grained soilsgrained soils

Hydrometer analysisHydrometer analysis

%100*%SWRRaP

TLKD

P%-passing cumulative

a- soil factor

R-hydrometer reading

R-corrected factor

Ws-weight of dry soil

D-soil diameter

K-hydrometer factor

L-depth of hydrometer in

Solution

time in minute

Soil particle size curve Uniformity coefficient UC=D60/D10

d10 d60

Weight and volume relation Weight and volume relation shipship

V

Va

Vw

Vs

W

Wa=0

Ww

Ws

W=Ws+Ww

V=Va+Vw+Vs

Vv =Va+Vw

V= Vv+Vs

Soils samplingSoils sampling•Disturbed sample for determine Disturbed sample for determine

properties physics of soilsproperties physics of soils•Undisturbed sample for determine Undisturbed sample for determine

properties mechanics of soils, we call properties mechanics of soils, we call undisturbed when Aundisturbed when ARR(%)<10%(%)<10%

•AARR :Area ratio :Area ratio•DDoo: Outside diameter of the sampling tube: Outside diameter of the sampling tube•DDii:Inside diameter of the sampling tube:Inside diameter of the sampling tube

100(%) 2

220

i

iR D

DDA

Soils unit weightSoils unit weightNatural water content:Natural water content:

Bulk unit weight:Bulk unit weight:

Dry unit weight: Dry unit weight: dd

Unit weight of particle solid: Unit weight of particle solid: ss

ws

eeSG

VW

1

s

s

VW

1001

VWs

%100s

w

WW

Another parameter Another parameter Void ratio: Void ratio:

Degree of saturation:Degree of saturation:

Saturated unit weight:Saturated unit weight:

Effective unit weight:Effective unit weight:

d

ds

s

v

VVe

w

s

v

w

eVVS

%100

Ws

sat eeG

1

ws

wsat eG

1

1'

Another parametersAnother parametersSpecific gravity:

Relative density:

Saturated water content:

ws

ss V

WG

%100minmax

max

eeeeDR

%10011

w

sdsat

Typical values of unit weight Typical values of unit weight of soilsof soils

Soil typeSoil type satsat(KN/M(KN/M33)) dd(KN/M(KN/M33))

GravelGravel 20 to 2220 to 22 15 to 1715 to 17

SandSand 18 to 2018 to 20 13 to 1613 to 16

SiltSilt 18 to 2018 to 20 14 to 1814 to 18

ClayClay 16 to 2216 to 22 14 to 2114 to 21

Description based on Description based on Relative densityRelative density

DDRR(%)(%) DescriptionDescription0 to 150 to 15 Very looseVery loose15 to 3515 to 35 LooseLoose35 to 6535 to 65 Medium denseMedium dense65 to 8565 to 85 DenseDense85 to 10085 to 100 Very denseVery dense

Soil consistenceSoil consistence

S hr inkagelim itW s

P las ticlim itW p

L iq u idlim itW L

A tte rbe rglim it

State of cohesion soilsState of cohesion soilsPlastic indexPlastic index

IIPP==LL--PP

Liquidity indexLiquidity index IILL==P

P

I

State of cohesion soilsState of cohesion soils

•If 0<If 0<<<ss : State solid : State solid

•If If ss<<<<pp: State semi-solid: State semi-solid

•If If pp<<<<LL: State Plastic: State Plastic

•If If >>L L : State Liquid: State Liquid

CH

MHCL

ML

CL-ML

Soil classificationSoil classificationUSCS:Unified soil classification USCS:Unified soil classification

system system (ASTM Test Designation D-2487)(ASTM Test Designation D-2487)

ASTM: American Society for ASTM: American Society for Testing and MaterialsTesting and Materials

Proposed by Casagrande in Proposed by Casagrande in 1942,this system was revised in 1942,this system was revised in

1952 by U.S Bureau of 1952 by U.S Bureau of Reclamation.Reclamation.

Coarse grained soilsCoarse grained soils

% R (4 .76 m m )> 0 .5% R (0 .07 5 m m )G rav e l

% R (4 .76 m m )< 0 .5% R (0 .07 5 m m )S and

% R (0 .07 5 m m )> 5 0%C oa rse g ra in ed so i ls

GravelGravel

U C < 4P oo r ly g ra de d G rav e l

G P

U C > 4W ell g rad ed G rav e l

G W

C lea n G rav e l% P (0 .07 5 m m )< 5%

GravelGravel

L o c ate d C L o r CHP oo rly g ra dedc lay e y G rav e l

G C -G P

L o ca te d M L o r M HP oo rly g ra ded

s i lty G rav e lG M -G P

L o ca te d C L-M LP oo r ly g rad ed clay ey

s i lty G rav e lG C -G M -G P

U C < 4O n p la stic Ch a rt C asa gra nd

L o c ate d C L or CHW ell g rad ed

c lay e y G rav e lG C -G W

L o ca te d M L o r M HW ell g rad eds i lty G rav e l

G M -G W

L o ca te d C L-M LW ell g rad ed clayey

s i lty G rav e lG C -G M -G W

U C > 4O n p la stic C h ar t Ca s ag ran de

M ixe d G rav e l5 % < % P (0 .0 75 m m )< 1 2%

GravelGravel

L o cate d C L o r C Hc lay e y G rav e l

G C

L o ca te d M L o r M H s i lty G rav e l

G M

L o ca te d C L-M L c lay e y s ilty G rav e l

G C -G M

M ixe d G rav e l% P (0 .0 7 5m m )> 1 2%

SandSand

U C < 6P oo rly g rad ed S and

S P

U C > 6W ell g ra de d S a nd

S W

C lea n S a nd% P (0 .07 5 m m )< 5%

SandSand

L o c ate d C L o r CHP oo rly g ra dedc lay e y S a nd

S C-S P

L o ca te d M L o r M HP oo rly g ra ded

s i lty S a ndS M -S P

L o ca te d C L-M LP oo r ly g rad ed clay ey

s i lty S a ndS C -S M -S P

U C < 6O n p la stic Ch a rt C asa gra nd

L o c ate d C L or CHW ell g rad edc lay e y S a nd

S C -S W

L o ca te d M L o r M HW ell g rad ed

s i lty S a ndS M -S W

L o ca te d C L-M LW ell g rad ed clayey

s i lty S a ndS C -S M -S W

U C > 6O n p la stic C h ar t Ca s ag ran de

M ixe d S a nd5 % <% P (0 .0 75 m m )< 1 2%

SandSand

L o cate d C L or C Hc laye y S a nd

S C

L o ca te d M L o r M H s i lty S a nd

S M

L o ca te d C L-M L c layey si lty S a nd

S C -S M

M ixe d S a nd% P (0 .0 7 5m m )> 1 2%

Fine grained soilsFine grained soils

C L C H

F o r C lay

M L M H

F o r S i lt

C L-M L

F o r S ilty c lay

% R (0 .07 5 m m )< 5 0%F ine g ra in ed so i ls

o n p la stic C h ar t C a sag ran de

Lean Clay(CL)Lean Clay(CL)

% S > % GL e an C layW ith sa nd

% S < % GL e an C lay

W ith g rav e l

1 5 % < % R (0 .0 75 m m )< 3 0%

% G < 1 5%S an dy

le an C lay

% G > 1 5%S an dy

le an C layw ith g rav e l

% S > % G

% S < 1 5%G ra v e lly

le an C lay

% S > 1 5%G ra ve lly

le an C layW ith sa nd

% S < % G

3 0 % < % R (0 .0 75 m m )< 5 0%

If:% R (0 .0 75 m m )< 1 5%L e an c lay

If% R (0 .0 75 m m )> 1 5%L o ok

Fat Clay(CH)Fat Clay(CH)

% S > % GF a t C lay

W ith sa nd

% S < % GF a t C lay

W ith g rav e l

1 5 % < % R (0.0 75 m m )< 3 0%

% G < 1 5%S an dy

F a t C lay

% G > 1 5%S an dy

F a t C layw ith g rav e l

% S > % G

% S < 1 5%G ra v e llyF a t C lay

% S > 1 5%G ra v e llyF a t C lay

W ith s a nd

% S < % G

3 0 % < % R (0 .0 75 m m )< 5 0%

If:% R (0 .0 75 m m )< 1 5%F a t c lay

If% R (0 .0 75 m m )> 1 5%L o ok

Silt (ML)Silt (ML)

% S > % GS ilt

W ith sa nd

% S < % GS ilt

W ith g rav e l

1 5 % < % R (0.0 75 m m )< 3 0%

% G < 1 5%S an dy

S i lt

% G > 1 5%S an dy

S i ltw ith g rav e l

% S > % G

% S < 1 5%G ra ve lly

S i lt

% S > 1 5%G ra ve lly

S i ltW ith sa nd

% S < % G

3 0 % < % R (0 .0 75 m m )< 5 0%

If:% R (0 .0 75 m m )< 1 5%S ilt

If% R (0 .0 75 m m )> 1 5%L o ok

Elastic Silt (MH)Elastic Silt (MH)

% S > % GE la stic S i ltW ith s a nd

% S < % GE la stic S i ltW ith g rav e l

1 5 % < % R (0 .0 75 m m )< 3 0%

% G < 1 5%S an dy

E la stic S i lt

% G > 1 5%S an dy

E la stic S i ltw i th g rav e l

% S > % G

% S < 1 5%G ra ve lly

E la stic S i lt

% S > 1 5%G ra v e lly

E la stic S i ltW ith sa nd

% S < % G

3 0 % < % R (0 .0 75 m m )< 5 0%

If:% R (0 .0 75 m m )< 1 5%E la stic S i lt

I f% R (0 .0 75 m m )> 1 5%L o ok

Silty clay (CL-ML)Silty clay (CL-ML)

% S > % GS ilty clay

W ith sa nd

% S < % GS ilty clay

W ith g rav e l

1 5 % < % R (0 .0 75 m m )< 3 0%

% G < 1 5%S an dy

S ilty clay

% G > 1 5%S an dy

S i lty clayw ith g rav e l

% S > % G

% S < 1 5%G ra v e llyS i lty clay

% S > 1 5%G ra ve llyS i lty clay

W ith sa nd

% S < % G

3 0 % < % R (0 .0 75 m m )< 5 0%

If:% R (0 .0 75 m m )< 1 5%S ilty clay

If% R (0 .0 75 m m )> 1 5%L o ok

Soil classificationSoil classification•AASHTO:Association American for AASHTO:Association American for

State Highway and Transportation State Highway and Transportation official, was developed 1929 and official, was developed 1929 and proposed by the committee on proposed by the committee on Materials for sub grades and Materials for sub grades and Granularity Type Boards of the Granularity Type Boards of the Highway Research Road in Highway Research Road in 1945(ASTM Test designation D-1945(ASTM Test designation D-3282;AASHTO method M145)3282;AASHTO method M145)

Granular Materials %P(0.075mm)<35%Granular Materials %P(0.075mm)<35%Group Group classificatclassificationion

A-1A-1 A-3A-3 A-2A-2A1-A1-aa

A1-A1-bb

A2-4A2-4 A2-5A2-5 A2-6A2-6 A2-7A2-7

%P(2mm)%P(2mm) <50<50%%

%P(0.425%P(0.425mm)mm)

<30<30%%

<50<50%%

>51>51%%

%P(0.075%P(0.075mm)mm)

<15<15%%

<25<25%%

<10<10%%

<35%<35% <35%<35% <35%<35% <35%<35%

WWLL<40<40 >40>40 <40<40 >40>40

IIPP<6%<6% NPNP <10<10 <10<10 >10>10 >10>10

Usual Usual type of type of materialsmaterials

Stone Stone fragment, fragment, gravel., gravel.,

sandsand

Fine Fine sandsand

Silty or clayey gravel and sandSilty or clayey gravel and sand

General General sub grade sub grade ratingrating

Excellence to goodExcellence to good

Silty - clay material Silty - clay material %P(0.075mm)>35%%P(0.075mm)>35%Group Group

classificationclassificationA-4A-4 A-5A-5 A-6A-6 A-7A-7

A-7-5A-7-5A-7-6A-7-6

%P(2mm)%P(2mm)%P(0.425mm)%P(0.425mm)%P(0.075mm)%P(0.075mm) >35%>35% >35%>35% >35%>35% >35%>35%

WWLL<40<40 >40>40 <40<40 >40>40

IIPP<10<10 <10<10 >10>10 >10>10

Usual type of Usual type of materialsmaterials

Silty soilsSilty soils Clayey soilsClayey soils

General General subgrade subgrade ratingrating

Fair to poorFair to poorFor A-7-5: IP<WL-30 For A-7-6: IP>WL-30

Group index GIGroup index GI

GI=(%P(0.075)-35)[0.2+0.005(WL-40)]+0.01(%P(0.075)-15)(IP-10)

Soil compactionSoil compaction• Standard Proctor testStandard Proctor test

• Modified Proctor testModified Proctor test

Specification for standard Proctor test(based on ASTM test Specification for standard Proctor test(based on ASTM test designation 698-91)designation 698-91)ItemItem Method AMethod A Method BMethod B Method CMethod CDiameter of moldDiameter of mold 101.6mm101.6mm 101.6mm101.6mm 152.4mm152.4mmVolume of moldVolume of mold 943.3cm943.3cm33 943.3cm943.3cm33 2124cm2124cm33

Weight of hammerWeight of hammer 24.4 N24.4 N 24.4 N24.4 N 24.4 N24.4 NHeight of hammer Height of hammer dropdrop

304.8mm304.8mm 304.8mm304.8mm 304.8mm304.8mm

Number of Number of hammer blows per hammer blows per layerlayer

2525 2525 5656

Number of layer Number of layer of compactionof compaction

33 33 33

Energy of Energy of compaction compaction

591.3KNm/591.3KNm/mm33

591.3KNm/591.3KNm/mm33

591.3KNm/591.3KNm/mm33

Soil to be usedSoil to be used %R(4.75)<2%R(4.75)<20%0%

Used soil Used soil %P(4.75)%P(4.75)

%R(4.75)>2%R(4.75)>20%0%

%R(9.5)<20%R(9.5)<20%%


%R(9.5)>20%R(9.5)>20%%

%R(19)<30%R(19)<30%%

Used soil Used soil %P(19)%P(19)

Specification for modified Proctor test(based on ASTM test designation 1557-Specification for modified Proctor test(based on ASTM test designation 1557-91)91)ItemItem Method AMethod A Method BMethod B Method CMethod CDiameter of moldDiameter of mold 101.6mm101.6mm 101.6mm101.6mm 152.4mm152.4mmVolume of moldVolume of mold 943.3cm943.3cm33 943.3cm943.3cm33 2124cm2124cm33

Weight of Weight of hammerhammer

44.5 N44.5 N 44.5 N44.5 N 44.5 N44.5 N

Height of Height of hammer drophammer drop

457.2mm457.2mm 457.2mm457.2mm 457.2mm457.2mm

Number of Number of hammer blows hammer blows per layerper layer

2525 2525 5656

Number of layer Number of layer of compactionof compaction

55 55 55

Energy of Energy of compaction compaction

2696KNm/m2696KNm/m33 2696KNm/2696KNm/mm33

2696KNm/2696KNm/mm33

Soil to be usedSoil to be used %R(4.75)<20%R(4.75)<20%%


%R(4.75)>2%R(4.75)>20%0%

%R(9.5)<20%R(9.5)<20%%


%R(9.5)>20%R(9.5)>20%%

%R(19)<30%R(19)<30%%

Used soil Used soil %P(19)%P(19)

Compaction equipmentCompaction equipment

Compaction curveCompaction curveMOISTURE DENSITY RELATIONSHIP CURVE

1.900

2.000

2.100

2.200

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00

Moisture content %

Dry

Den

sity

g/m

3

Wopt

dmax

California Bearing California Bearing Ratio(CBR)Ratio(CBR)•For study the strength of soils after For study the strength of soils after

compacting in optimum state.compacting in optimum state.1-Recompaction the soil in optimum 1-Recompaction the soil in optimum

statestate2-Determine CBR in dry condition2-Determine CBR in dry condition3-Saturated the soil under water 4 3-Saturated the soil under water 4

daysdays4-Determine CBR in soaked condition4-Determine CBR in soaked conditionCBR=CBR= %100

..standard..

loadunit

loadunitTest

BEARING RATIO TEST (CBR)

Project: Pochentong Airport Job No.Location of Project: Pochentong Airport Boring No 2 Sample No.2Description of Soil: Tested by: Mr. Men Tharith Date of Testing. 16/05/2002

CBR Test Load Data (soaked)Mold

Surrcharge Piston load Load.

Penetration. dial reading kgf/cm2

mm ( unit )0.000 0 01.00 0.045 2.30772.00 0.075 3.84623.00 0.11 5.6414.00 0.145 7.43595.00 0.175 8.97446.00 0.21 10.7697.00 0.25 12.8218.00 0.28 14.3599.00 0.31 15.89710.00 0.34 17.436

CBR(2.54)= 7.1429

Acceppted CBR= 7.14

Final water Top 7.9conten, w% Midle 7.8

(soaked) Bottom 7.99sample Averagee 7.8967

Wet unit wt. = 2.2952 g/cm3 Dry unit wt. = 2.13444 g/cm3

Wet unit wt.(soaked) = 2.303 g/cm3

Curve CBR Test

0

2

4

6

8

10

12

14

16

18

20

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0

Renetration (mm)

Load

(kgf

/cm

2 )

P2.54

Penetration(mm)Penetration(mm) Standard unit Standard unit load(Mpa)load(Mpa)

2.52.5 6.96.9

55 10.310.3

7.57.5 1313

1010 1616

12.712.7 1818

CBR equipmentCBR equipment

CBR equipmentCBR equipment

CBR special for field CBR special for field controlcontrol•Compaction the soils in optimum state with Compaction the soils in optimum state with

different energydifferent energy1-Compaction 10 blows per layer and 1-Compaction 10 blows per layer and

saturated the soil under water during 4 dayssaturated the soil under water during 4 days2-Compaction 25 blows per layer and 2-Compaction 25 blows per layer and

saturated the soil under water during 4 dayssaturated the soil under water during 4 days3-Compaction 55 blows per layer and 3-Compaction 55 blows per layer and

saturated the soil under water during 4 dayssaturated the soil under water during 4 days4-Determine CBR in soaked condition for each4-Determine CBR in soaked condition for each5-Plotted values CBR with dry density on 5-Plotted values CBR with dry density on

chartchart

CBR chartCBR chart

CBRCBR GeneraGeneral ratingl rating

UsesUses Classification systemClassification system

USCSUSCS AASHTOAASHTO

0-30-3 Very Very poorpoor

SubgradSubgradee

OH,CH,MH,OOH,CH,MH,OLL

A5,A6,A7A5,A6,A7

3-73-7 Poor to Poor to fairfair

SubgradSubgradee

OH,CH,MH,OOH,CH,MH,OLL

A4,A5,A6,AA4,A5,A6,A77

7-207-20 FairFair SubbaseSubbase OL,CL,ML,SCOL,CL,ML,SC,SM,SP,SM,SP

A2,A4,A6,AA2,A4,A6,A77

20-20-5050

GoodGood BaseBasesubbasesubbase

GM,GC,SW,GM,GC,SW,SM,SP,GPSM,SP,GP

A1b,A2-5, A1b,A2-5, A3,A2-6A3,A2-6

>50>50 ExcelleExcellentnt

BaseBase GW,GMGW,GM A1-a,A2-4A1-a,A2-4A3A3

Control soils compactionControl soils compaction

•%Compaction=%Compaction=

•Determine field density by Determine field density by using:using:

1-Undisturbed sampling1-Undisturbed sampling2-Sand cone method2-Sand cone method3-Balloon density equipment 3-Balloon density equipment 4-Nuclear method4-Nuclear method

max

. %100

d

fieldd

Sand cone methodSand cone method

Control CBRControl CBR• Field CBRField CBR• By using Dynamic cone penetration test DCPBy using Dynamic cone penetration test DCP

1-Kleyn and Van Heerden(601-Kleyn and Van Heerden(6000cone) : Lg.(CBR)=2.632-cone) : Lg.(CBR)=2.632-1.28Lg.(mm/blow)1.28Lg.(mm/blow)

2-Smith and Pratt (302-Smith and Pratt (3000cone) : Lg.(CBR)=2.555-cone) : Lg.(CBR)=2.555-

1.145Lg.(mm/blow)1.145Lg.(mm/blow) 3-VanVuuren (303-VanVuuren (3000 cone) : Lg.(CBR)=2.503- cone) : Lg.(CBR)=2.503-

1.15Lg.(mm/blow)1.15Lg.(mm/blow) 4-TRRL Road Note 8(604-TRRL Road Note 8(6000cone) : Lg.(CBR)=2.48-cone) : Lg.(CBR)=2.48-

1.057Lg(mm/blow)1.057Lg(mm/blow)

• By using CBR ChartBy using CBR Chart

CBR controlCBR control

Shear strength of soilsShear strength of soils•Total Stress Analysis (TSA)Total Stress Analysis (TSA)-for clayey soils with permeability very low, -for clayey soils with permeability very low,

so for short term loading soils and water so for short term loading soils and water work together.work together.

•Effective Stress Analysis(ESA)Effective Stress Analysis(ESA)-for sandy soils with high permeability,so for -for sandy soils with high permeability,so for

short term loading soils work yourself onlyshort term loading soils work yourself only•For analyze soils stability For analyze soils stability

problems(bearing capacity,slope problems(bearing capacity,slope stability,lateral pressure on earth-retaining stability,lateral pressure on earth-retaining structure)structure)

Effective stress in soils massEffective stress in soils mass

•Total stress Total stress sat.sat.ZZ

•Effective stress Effective stress ’’00’’..ZZ

•Pore water pressure U= Pore water pressure U= ww.Z.Z’’= = satsat- ww

ww unit weight of water unit weight of water

Mohr-Coulomb CriteriaMohr-Coulomb Criteria•The shear stress on the failure The shear stress on the failure

plan as a linear function of the plan as a linear function of the normal stress (Coulomb,1776)normal stress (Coulomb,1776) c c tg tg

•A material fails because of a A material fails because of a critical combination of normal critical combination of normal stress and shear stress, and not stress and shear stress, and not from either maximum normal or from either maximum normal or shear stress alone (Mohr,1900)shear stress alone (Mohr,1900)

Failure planFailure planx

y

f

Mohr-Coulomb failure Mohr-Coulomb failure criteriacriteria

C

Line Coulomb’s: tgC

Unconfined compression Unconfined compression testtest•Type TSA testType TSA test

•Undisturbed sample Undisturbed sample with hwith h00=2d=2doo

•Speed Speed =2%/min=2%/min=2%/min==2%/min=h/h/

hh00**100%/min100%/min

•For determine For determine undrained cohesion undrained cohesion Cu, in this case Cu, in this case u=0u=0

qu

Mohr circleMohr circle

0 qu

Cu

Direct shear testDirect shear test• Type Type

undrained test undrained test or drained testor drained test

• Undisturbed Undisturbed samplesample

• For determine For determine cohesion of cohesion of soils soils C C and and internal friction internal friction angle of soils angle of soils

• Build by Build by CasagrandeCasagrande

Shear boxShear boxPorous stone

Shear force

Shear box

Normal force

Porous stone

Loading plate

Soil sample

Determine C & Determine C &

22)(

ii

iiii

nntg

ntgC ii

C

0

Triaxial testTriaxial test

•UU test: Unconsolidated undrained UU test: Unconsolidated undrained testtest

•CU test: Consolidated undrained testCU test: Consolidated undrained test

•CD test: Consolidated drained testCD test: Consolidated drained test

Triaxial equipmentTriaxial equipment

UU testUU test

0 qu

Cu

General relationship of consistency General relationship of consistency and unconfined compression and unconfined compression strength of claystrength of clay

ConsistencyConsistency qquu(KN/m(KN/m22))Very softVery soft 0-250-25

SoftSoft 25-5025-50Medium stiffMedium stiff 50-10050-100

StiffStiff 100-200100-200Very stiffVery stiff 200-400200-400

hardhard >400>400

Empirical equation related to Cu and Empirical equation related to Cu and ’’00ReferenceReference RelationshipRelationship RemarksRemarksSkempton Skempton (1957)(1957)

Cu=[0.11+0.0037.ICu=[0.11+0.0037.IPP].].’’00

Cu from vane shear Cu from vane shear testtest

For normally For normally consolidated consolidated clayclay

Chandler(19Chandler(1988)88)

Cu=[0.11+0.0037.ICu=[0.11+0.0037.IPP].].’’cc

Cu from vane shear Cu from vane shear test test ’’c c preconsolidation preconsolidation pressurepressure

Can be use Can be use for over for over consolidated consolidated clay not valid clay not valid for sensitive for sensitive clayclay

Jamiolkowski Jamiolkowski et al (1985)et al (1985)

Cu=[0.23 Cu=[0.23 0.04].0.04].’’cc

For lightly For lightly over over consolidated consolidated clayclay

CU & CD testCU & CD test

0

C

Typical values of drained Angle of Typical values of drained Angle of friction for Sand and Siltfriction for Sand and Silt

Soil typeSoil type (degree)(degree)Sand : Rounded grainsSand : Rounded grains

Loose Loose 27-3027-30Medium denseMedium dense 30-3530-35DenseDense 35-3835-38

Sand : Angular grainsSand : Angular grainsLoose Loose 30-3530-35Medium denseMedium dense 35-4035-40DenseDense 40-4540-45Gravel with some sandGravel with some sand 34-4834-48SiltsSilts 26-3526-35

Typical values of drained Angle of Typical values of drained Angle of friction and Cohesion for Gravelfriction and Cohesion for GravelUSCSUSCS degree)degree) C(KN/mC(KN/m22))GWGW 40 540 5 00GPGP 38 638 6 00GMGM 36 436 4 00GCGC 34 434 4 00

GM-MLGM-ML 35 535 5 00GM-GCGM-GC 33 333 3 2 22 2GC-CLGC-CL 29 429 4 3 33 3GC-CHGC-CH 28 428 4 4 44 4

Typical values of drained Angle of Typical values of drained Angle of friction and Cohesion for Sandfriction and Cohesion for SandUSCSUSCS degree)degree) C(KN/mC(KN/m22))SWSW 38 538 5 00SPSP 36 636 6 00SMSM 34 334 3 00SCSC 32 432 4 00

SM-MLSM-ML 34 334 3 00SM-SCSM-SC 31 331 3 5 55 5SC-CLSC-CL 28 428 4 5 55 5SC-CHSC-CH 27 327 3 10 1010 10

Typical values of drained Angle of Typical values of drained Angle of friction and Cohesion for Fine grained friction and Cohesion for Fine grained soilssoilsUSCSUSCS degree)degree) C(KN/mC(KN/m22))

MLML 33 433 4 00CL-MLCL-ML 30 430 4 15 1015 10

CLCL 27 427 4 20 1020 10CHCH 22 422 4 25 1025 10OLOL 25 425 4 10 510 5OHOH 22 422 4 10 510 5MHMH 24 624 6 5 55 5

Stress in soils massStress in soils mass

O

M

Z

M1

Z

Q

2a=L

2b=B

Determine stress in soils massDetermine stress in soils mass1-Stress at the center of footing1-Stress at the center of footingvMvM=4.I=4.I22.q = 4.K.q.q = 4.K.q

BLQq

1

1212

112

41

2222

22

22

22

2222

22

2 nmnmnmmnarctg

nmnm

nmnmnmmnI

ZBm

2

ZLn

2

aZ

Determine stress in soils massDetermine stress in soils mass2-Stress at the corner of footing2-Stress at the corner of footingvM1vM1=I=I22.q = K.q.q = K.q

BLQq

1

1212

112

41

2222

22

22

22

2222

22

2 nmnmnmmnarctg

nmnm

nmnmnmmnI

ZBm

ZLn

aZ2

Determine stress in soil mass Determine stress in soil mass by using tableby using table b/a

K

0

0.1

0.2

1/3

0.4

0.5

2/3

1

1.5

2

2.5

3

5

10

0 0.000 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250 0.250

0.2 0.000 0.137 0.204 0.234 0.240 0.244 0.247 0.249 0.249 0.249 0.249 0.249 0.249 0.249 0.249 0.4 0.000 0.076 0.136 0.187 0.202 0.218 0.231 0.240 0.243 0.244 0.244 0.244 0.244 0.244 0.244 0.5 0.000 0.061 0.113 0.164 0.181 0.200 0.218 0.232 0.238 0.239 0.240 0.240 0.240 0.240 0.240 0.6 0.000 0.051 0.096 0.143 0.161 0.182 0.204 0.223 0.231 0.233 0.234 0.234 0.234 0.234 0.234 0.8 0.000 0.037 0.071 0.111 0.127 0.148 0.173 0.200 0.214 0.218 0.219 0.220 0.220 0.220 0.220 1 0.000 0.028 0.055 0.087 0.101 0.120 0.145 0.175 0.194 0.200 0.202 0.203 0.204 0.205 0.205

1.2 0.000 0.022 0.043 0.069 0.081 0.098 0.121 0.152 0.173 0.182 0.185 0.187 0.189 0.189 0.189 1.4 0.000 0.018 0.035 0.056 0.066 0.080 0.101 0.131 0.154 0.164 0.169 0.171 0.174 0.174 0.174 1.5 0.000 0.016 0.031 0.051 0.060 0.073 0.092 0.121 0.145 0.156 0.161 0.164 0.166 0.167 0.167 1.6 0.000 0.014 0.028 0.046 0.055 0.067 0.085 0.112 0.136 0.148 0.154 0.157 0.160 0.160 0.160 1.8 0.000 0.012 0.024 0.039 0.046 0.056 0.072 0.097 0.121 0.133 0.140 0.143 0.147 0.148 0.148 2 0.000 0.010 0.020 0.033 0.039 0.048 0.061 0.084 0.107 0.120 0.127 0.131 0.136 0.137 0.137

2.5 0.000 0.007 0.013 0.022 0.027 0.033 0.043 0.060 0.080 0.093 0.101 0.106 0.113 0.115 0.115 3 0.000 0.005 0.010 0.016 0.019 0.024 0.031 0.045 0.061 0.073 0.081 0.087 0.096 0.099 0.099 4 0.000 0.003 0.006 0.009 0.011 0.014 0.019 0.027 0.038 0.048 0.055 0.060 0.071 0.076 0.076 5 0.000 0.002 0.004 0.006 0.007 0.009 0.012 0.018 0.026 0.033 0.039 0.043 0.055 0.061 0.062 10 0.000 0.000 0.001 0.002 0.002 0.002 0.003 0.005 0.007 0.009 0.011 0.013 0.020 0.028 0.032 15 0.000 0.000 0.000 0.001 0.001 0.001 0.001 0.002 0.003 0.004 0.005 0.006 0.010 0.016 0.021 20 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.001 0.002 0.002 0.003 0.004 0.006 0.010 0.016

50 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.002 0.006

ConsolidationConsolidation

Settlement of soilsSettlement of soils

hi

S

Ho

S

ho

Before loading After loading

Consolidation curveConsolidation curve

e

Log’p

e1e2

e3

e4

Determination parameter of Determination parameter of consolidationconsolidationNatural void ratioNatural void ratio

Void ratio after consolidationVoid ratio after consolidation

Swell indexSwell index

Compression indexCompression index

0

00

HHhe

0

00

HhHhe i

i

12

21

loglog

eeCs

34

43

loglog

eeCc

Determination parameter of Determination parameter of consolidationconsolidationModulus of elasticityModulus of elasticity

ee and and located between 100 Kpa to 200KPalocated between 100 Kpa to 200KPa

Compression indexCompression index

Swell indexSwell index

eemE ks

01.

Types of soil emKuNsMBaF mk

GaRs½yeTAnwgemKuNes<at eo0.45

0.55 0.65 0.75 0.85 0.95 1.05

Sandy silt

Silt

Clay

4.00

5.00 -

4.00

5.00 -

3.50

4.50

6.00

3.00

4.00

6.00

2.00

3.00

5.50

-

2.50

5.00

-

2.00

4.50

Soil type RbePTdI

Sand xSac;/ l ,ayxSac; 0.30 0.74

Silt l ,aydI\dæ 0.35 0.62

Clay dI\dæ 0.42 0.40

Elastic parameter of various Elastic parameter of various soilssoilsType of soilsType of soils Modulus of Modulus of

elasticity elasticity Es(Mpa)Es(Mpa)

Poisson’s ratio Poisson’s ratio ss

Loose sandLoose sand 10-2510-25 0.20-0.400.20-0.40Medium dense Medium dense sandsand

15-3015-30 0.25-0.400.25-0.40

Dense sandDense sand 35-5535-55 0.30-0.450.30-0.45Silty sandSilty sand 10-2010-20 0.20-0.400.20-0.40Sand and Sand and gravelgravel

70-17070-170 0.15-0.350.15-0.35

Soft claySoft clay 4-204-200.20-0.500.20-0.50Medium stiff Medium stiff

clayclay20-4020-40

Stiff clayStiff clay 40-10040-100

Coefficient of consolidationCoefficient of consolidationLog t

h

t1

t1/4

t 100

t 501min

Determination coefficient of Determination coefficient of consolidationconsolidationCoefficient of consolidation from Coefficient of consolidation from Casagrande method CCasagrande method Cvv[m[m22/s]/s]

hh00- initial thickness of sample- initial thickness of samplePermeability coefficientPermeability coefficient

Coefficient of compressibilityCoefficient of compressibility

Coefficient of volume changeCoefficient of volume change

50

2

197.0tHCv

2500

hH

eaCK wvv

1..

eav

01 eam v

v

Typical values of coefficient Typical values of coefficient of consolidation Cof consolidation Cvv[cm[cm22/s]/s]

Liquid limitLiquid limit Lower limit Lower limit of of

recompressirecompressionon

UndisturbUndisturbed virgin ed virgin

compressicompressionon

Upper limit Upper limit remoldedremolded

3030 3.5*103.5*10-2-2 5*105*10-3-3 1.2*101.2*10-3-3

6060 3.5*103.5*10-3-3 1*101*10-3-3 3*103*10-4-4

100100 4*104*10-4-4 2*102*10-4-4 1*101*10-4-4

Source U.S Navy 1962

In situ testIn situ test

•Static cone penetration testStatic cone penetration test•Dynamic cone penetration test Dynamic cone penetration test

DCPDCP•Standard penetration testStandard penetration test•Shear vane testShear vane test•Pocked penetration testPocked penetration test

Static cone penetration Static cone penetration testtest

K

c

NqCu 0

0'log38.01.0

cqArctg

E=2.qc

qc:cone resistance

Nk=20

Dynamic cone penetration testDynamic cone penetration testAHM

MMeMqd

..)'.(

qd :cone resistance

M:weight of hammer

M’:weight of rods

A:cone area

H:height hammer falling

e:penetration for one blow

Standard penetration testStandard penetration test

Index SPTIndex SPTN value is amount of blows for penetration split spoon sampler in soils 30 cm

N=N1+N2

Ncor= CN.Nfield

CN = 0.77logD.

2000

Peck1974

0'178.9

NC Liao & Whihman 1986

0'01.012

NC Skempton1986

6.95'

log25.11 0NC Seed 1975

For fine sand or silt saturated with N >15

Ncor=15+0.5 (Nfield-15)

Relationship of SPT and properties Relationship of SPT and properties mechanics of soilsmechanics of soils

2020 N H a t a n a k a & U c h i d a 1 9 9 6 200054.03.01.27 NN W o l f f 1 9 8 9

1518 N F o r r o a d a n d B r i d g e s d e s i g n s Mr ab ;f ñ;l ;n ig s <an

2736.0 N F o r b u i l d i n g d e s i g n s Mr ab ; G aK ar

2045.0 N i n g e n e r a l s Mr ab ;k r N IT UeT A

E ( K P a ) = 7 6 6 N F o r s a n d s a t u r a t e d s Mr ab ;x Sac ;C aMT wk

E ( K P a ) = 5 0 0 ( N + 1 5 ) F o r d e n s e s a n d s Mr ab ; x Sac ;h ab ; E ( K P a ) = 2 6 0 0 N F o r d e n s e s a n d s Mr ab ; x Sac ;h ab ; E ( K P a ) = 6 0 0 ( N + 6 ) F o r G r a v e l l y s a n d ( N < 1 5 ) s Mr ab ; RK Ys l ay x Sac ; E ( K P a ) = 6 0 0 ( N + 6 ) + 2 0 0 0 F o r G r a v e l l y s a n d ( N > 1 5 ) s Mr ab ; RK Ys l ay x Sac ; E ( K P a ) = 3 2 0 ( N + 1 5 ) F o r C l a y e y S a n d s Mr ab ; x Sac ; l ay d I\ d æ E ( K P a ) = 3 0 0 ( N + 6 ) F o r S i l t , s a n d y s i l t , c l a y e y s i l t s Mr ab ; d Il , ay m :d æ

Relationship of SPT and properties Relationship of SPT and properties mechanics of soilsmechanics of soils

• Undrained cohesion Cu=K.N Stroud(1974)Undrained cohesion Cu=K.N Stroud(1974)

3.5KPa <K <6KPa in general we take 3.5KPa <K <6KPa in general we take K=4.4KPaK=4.4KPa

• Cu=29.NCu=29.N0.720.72 Hara et al(1971) Hara et al(1971)

Soils type Nblows

DR %

degree

KN/m3

Very loose 0 4 0 15 < 28 11 16

Loose 4 10 15 35 28 30 14 18

Medium dense

10 30 35 65 30 36 17 20

Dense; 30 50 65 85 36 41 17 22

Very dense > 50 85 100 > 41 20 23

Soils type N qu KPa

Very soft < 2 < 25

Soft 2 4 25 50

Medium 4 8 50 100

Stiff 8 15 100 200

Very stiff 15 30 200 400

Hard > 30 > 400

Thank you for your Thank you for your attentionattention

• Mr. Sieng PEOUMr. Sieng PEOU• Master science of Master science of

geotechnical geotechnical engineeringengineering

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Advance Soil Mechanics