advance soil mechanics [compatibility mode]

8/8/2019 Advance Soil Mechanics [Compatibility Mode]

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1

Advance Soil mechanics Advance Soil mechanics

Present by Mr. Sieng PEOU Present by Mr. Sieng PEOU

Master science of geotechnical Master science of geotechnical engineering engineering

Tel Tel- -011 874 974 011 874 974 email: [email protected] email: [email protected]

Soils particle sizeSoils particle size

19.5mm>d>4.76mm

.

Gravel

4.76mm>d>0.075mm

Sand

Coarse grained soils

0.075mm>d>0.002mm

Silt

d<0.002mm

Clay

Fine grained soils

Soils



2

Sieve analysis methodSieve analysis method

For coarseFor coarsegrained soilsgrained soils

Retained cumulativeRetained cumulative

%R=%R= %100.

..×

weight total

cumulativeretained weight

Passing cumulative

%P = 100-%R



3

Logarithm scaleLogarithm scale

Log d

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)

HydrometerHydrometer

analysisanalysis

For fineFor finegrained soilsgrained soils



4

Hydrometer analysisHydrometer analysis

%100*%S

W

R RaP

∆+=

T

LK D =

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

Τ− time in minute

Soil particle size curve Uniformity coefficient UC=D60/D10

d10 d60



5

Weight and volumeWeight and volumerelationshiprelationship

V

Va

Vw

Vs

W

Wa=0

Ww

Ws

W=Ws+Ww

V=Va+Vw+Vs

Vv =Va+Vw

V= Vv+Vs



6

Soils samplingSoils sampling

Disturbed sample for determine propertiesDisturbed sample for determine propertiesphysics of soilsphysics of soils

Undisturbed sample for determineUndisturbed sample for determineproperties mechanics of soils, we callproperties mechanics of soils, we callundisturbed when A undisturbed when A R R (%)<10%(%)<10%

A A R R :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

22

0

×−

=i

i

R D

D D

A

Soils unit weightSoils unit weight

Natural water content:Natural water content:

Bulk unit weight:Bulk unit weight:γ=γ=

Dry unit weight:Dry unit weight: γ γ dd==

Unit weight of particle solid:Unit weight of particle solid: γ γ ss==

w

s

e

eSG

V

W γ ×

+

×+=

1

s

s

V

W

1001

ω

γ

+

=V

W s

%100×=s

w

W

W ω



7

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

d s

s

v

V

V e ρ

ρ ρ −==

w

s

v

w

eV

V S

ρ

ω ρ

×

×=×= %100

W s

sat e

eGγ γ ×

+

+=

1

ws

wsat e

Gγ γ γ γ ×

+

−=−=

1

1'

Another parameters Another parameters

Specific gravity:

Relative density:

Saturated water content:

ws

ss

V

W G

γ ×=

%100minmax

max ×−

−=

ee

ee D R

%10011

××

−= w

sd

sat ρ ρ ρ

ω



8

Typical values of unit weight of soilsTypical values of unit weight of soils

Soil typeSoil type γ γ satsat(KN/M(KN/M33)) γ γ 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 ase onDescription ase onRelative densityRelative density

DDR R (%)(%) DescriptionDescription

0 to 150 to 15 Very loose Very loose

15 to 3515 to 35 LooseLoose

35 to 6535 to 65 Medium denseMedium dense

65 to 8565 to 85 DenseDense

85 to 10085 to 100 Very dense Very dense



9

Soil consistenceSoil consistence

Shrinkagelimit

Ws

Plasticlimit

Wp

Liquidlimit

WL

Atterberg

limit

State of cohesion soilsState of cohesion soils

Plastic indexPlastic index

IIPP==ωωLL--ωωPP

Liquidity indexLiquidity index

IILL==

P

P

I

ω ω −



10

State of cohesion soilsState of cohesion soils

If 0<If 0<ωω<<ωωss : State solid: State solid

If If ωωss<<ωω<<ωωpp: State semi: State semi--solidsolid

If If ωωpp<<ωω<<ωωLL: State Plastic: State Plastic

If If ωω>>ωωLL : State Liquid: State Liquid



11

CH

MHCL

ML

CL-ML



12

Soil classificationSoil classification

USCS:Unified soil classification systemUSCS:Unified soil classification system

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

ASTM: American Society for Testing ASTM: American Society for Testingand Materialsand Materials

Proposed by Casagrande in 1942,thisProposed by Casagrande in 1942,this

system was revised in 1952 by U.Ssystem was revised in 1952 by U.SBureau of Reclamation.Bureau of Reclamation.

Coarse grained soilsCoarse grained soils

%R(4.76mm)>0.5%R(0.075mm)

Gravel

%R(4.76mm)<0.5%R(0.075mm)

Sand

%R(0.075mm)>50%

Coarse grained soils



13

GravelGravel

UC<4

Poorly graded Gravel

GP

UC>4

Well graded Gravel

GW

Clean Gravel

%P(0.075mm)<5%

GravelGravel

Located CL or CH

Poorly graded

clayey Gravel

GC-GP

Located ML or MH

Poorly graded

silty Gravel

GM-GP

Located CL-ML

Poorly graded clayey

silty Gravel

GC-GM-GP

UC<4

On plastic Chart Casagrand

Located CL or CH

Well graded

clayey Gravel

GC-GW

Located ML or MH

Well graded

silty Gravel

GM-GW

Located CL-ML

Well graded clayey

silty Gravel

GC-GM-GW

UC>4

On plastic Chart Casagrande

Mixed Gravel

5%<%P(0.075mm)<12%



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GravelGravel

Located CL or CH

clayey Gravel

GC

Located ML or MH

silty Gravel

GM

Located CL-ML

clayey silty Gravel

GC-GM

Mixed Gravel

%P(0.075mm)>12%

SandSand

UC<6

Poorly graded Sand

SP

UC>6

Well graded Sand

SW

Clean Sand

%P(0.075mm)<5%



15

SandSand

Located CL or CH

Poorly graded

clayey SandSC-SP

Located ML or MH

Poorly graded

silty SandSM-SP

Located CL-ML

Poorly graded clayey

silty SandSC-SM-SP

UC<6

On plastic Chart Casagrand

Located CL or CH

Well graded

clayey SandSC-SW

Located ML or MH

Well graded

silty SandSM-SW

Located CL-ML

Well graded clayey

silty SandSC-SM-SW

UC>6

On plastic Chart Casagrande

Mixed Sand

5%<%P(0.075mm)<12%

SandSand

Located CL or CH

clayey Sand

SC

Located ML or MH

silty Sand

SM

Located CL-ML

clayey silty Sand

SC-SM

Mixed Sand

%P(0.075mm)>12%



16

Fine grained soilsFine grained soils

CL CH

For Clay

ML MH

For Silt

CL-ML

For Silty clay

%R(0.075mm)<50%

Fine grained soils

on plastic Chart Casagrande

Lean Clay(CL)Lean Clay(CL)

%S>%G

Lean Clay

With sand

%S<%G

Lean Clay

With gravel

15%<%R(0.075mm)<30%

%G<15%

Sandy

lean Clay

%G>15%

Sandy

lean Clay

with gravel

%S>%G

%S<15%

Gravelly

lean Clay

%S>15%

Gravelly

lean Clay

With sand

%S<%G

30%<%R(0.075mm)<50%

If:%R(0.075mm)<15%

Lean clay

If%R(0.075mm)>15%

Look



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Fat Clay(CH)Fat Clay(CH)

%S>%G

Fat Clay

With sand

%S<%G

Fat Clay

With gravel

15%<%R(0.075mm)<30%

%G<15%

Sandy

Fat Clay

%G>15%

Sandy

Fat Clay

with gravel

%S>%G

%S<15%

Gravelly

Fat Clay

%S>15%

Gravelly

Fat Clay

With sand

%S<%G

30%<%R(0.075mm)<50%

If:%R(0.075mm)<15%

Fat clay

If%R(0.075mm)>15%

Look

Silt (ML)Silt (ML)

%S>%G

Silt

With sand

%S<%G

Silt

With gravel

15%<%R(0.075mm)<30%

%G<15%

Sandy

Silt

%G>15%

Sandy

Silt

with gravel

%S>%G

%S<15%

Gravelly

Silt

%S>15%

Gravelly

Silt

With sand

%S<%G

30%<%R(0.075mm)<50%

If:%R(0.075mm)<15%

Silt

If%R(0.075mm)>15%

Look



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Elastic Silt (MH)Elastic Silt (MH)

%S>%G

Elastic Silt

With sand

%S<%G

Elastic Silt

With gravel

15%<%R(0.075mm)<30%

%G<15%

Sandy

Elastic Silt

%G>15%

Sandy

Elastic Silt

with gravel

%S>%G

%S<15%

Gravelly

Elastic Silt

%S>15%

Gravelly

Elastic Silt

With sand

%S<%G

30%<%R(0.075mm)<50%

If:%R(0.075mm)<15%

Elastic Silt

If%R(0.075mm)>15%

Look

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

%S>%G

Silty clay

With sand

%S<%G

Silty clay

With gravel

15%<%R(0.075mm)<30%

%G<15%

Sandy

Silty clay

%G>15%

Sandy

Silty clay

with gravel

%S>%G

%S<15%

Gravelly

Silty clay

%S>15%

Gravelly

Silty clay

With sand

%S<%G

30%<%R(0.075mm)<50%

If:%R(0.075mm)<15%

Silty clay

If%R(0.075mm)>15%

Look



19

Soil classificationSoil classification

AASHTO:Association American for AASHTO:Association American forState Highway and TransportationState Highway and Transportationofficial, was developed 1929 andofficial, was developed 1929 andproposed by the committee onproposed by the committee onMaterials for sub grades andMaterials for sub grades andGranularity Type Boards of theGranularity Type Boards of theHighway Research Road inHighway Research Road in1945(ASTM Test designation D1945(ASTM Test designation D--3282;AASHTO method M145)3282;AASHTO method M145)

Granular MaterialsGranular Materials%P(0.075mm)<35%%P(0.075mm)<35%

GroupGroupclassificationclassification

A A--11 A A--33 A A--22 A1 A1--aa A1 A1--bb A2 A2--44 A2 A2--55 A2 A2--66 A2 A2--77

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

%P(0.425mm)%P(0.425mm) <30%<30% <50%<50% >51%>51%

%P(0.075mm)%P(0.075mm) <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 type of Usual type of materialsmaterials

StoneStonefragment,fragment,

gravel, sandgravel, sand

FineFinesandsand

Silty or clayey gravel and sandSilty or clayey gravel and sand

General subGeneral subgrade ratinggrade rating

Excellence to goodExcellence to good



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SiltySilty -- clay material %P(0.075mm)>35%clay material %P(0.075mm)>35%

GroupGroupclassificationclassification

A A--44 A A--55 A A--66 A A--77

A A--77--55

A A--77--66

%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

GeneralGeneralsubgrade ratingsubgrade rating

Fair to poorFair to poor

For 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)



21

Soil compactionSoil compaction

Standard Proctor testStandard Proctor test

Modified Proctor testModified Proctor test

Specification for standard Proctor test(based on ASTM testSpecification for standard Proctor test(based on ASTM testdesignation 698designation 698--91)91)

ItemItem Method A Method A Method BMethod B Method CMethod C

Diameter of moldDiameter of mold 101.6mm101.6mm 101.6mm101.6mm 152.4mm152.4mm

Volume of mold Volume 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 N

Height of hammer dropHeight of hammer drop 304.8mm304.8mm 304.8mm304.8mm 304.8mm304.8mm

Number of hammerNumber of hammerblows per layerblows per layer

2525 2525 5656

Number of layer of Number of layer of compactioncompaction

33 33 33

Energy of compactionEnergy of compaction 591.3KNm/m591.3KNm/m33 591.3KNm/m591.3KNm/m33 591.3KNm/m591.3KNm/m33

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

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

%R(4.75)>20%%R(4.75)>20%

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


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

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

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



22

Specification for modified Proctor test(based on ASTM testSpecification for modified Proctor test(based on ASTM testdesignation 1557designation 1557--91)91)

ItemItem Method A Method A Method BMethod B Method CMethod C

Diameter of moldDiameter of mold 101.6mm101.6mm 101.6mm101.6mm 152.4mm152.4mm

Volume of mold Volume of mold 943.3cm943.3cm33 943.3cm943.3cm33 2124cm2124cm33

Weight of hammerWeight of hammer 44.5 N44.5 N 44.5 N44.5 N 44.5 N44.5 N

Height of hammer dropHeight of hammer drop 457.2mm457.2mm 457.2mm457.2mm 457.2mm457.2mm

Number of hammerNumber of hammerblows per layerblows per layer

2525 2525 5656

Number of layer of Number of layer of compactioncompaction

55 55 55

Energy of compactionEnergy of compaction 2696KNm/m2696KNm/m33 2696KNm/m2696KNm/m33 2696KNm/m2696KNm/m33

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


%R(4.75)>20%%R(4.75)>20%

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

Used soilUsed soil

%P(9.5)%P(9.5)

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

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

Used soilUsed soil

%P(19)%P(19)

Compaction equipmentCompaction equipment



23

Compaction curveCompaction curve

MOISTURE 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 %

D r y D e n s i t y g / m 3

Wopt

ρdmax

California Bearing Ratio(CBR)California Bearing Ratio(CBR)

For study the strength of soils afterFor study the strength of soils aftercompacting in optimum state.compacting in optimum state.

11--Recompaction the soil in optimum stateRecompaction the soil in optimum state

22--Determine CBR in dry conditionDetermine CBR in dry condition33--Saturated the soil under water 4 daysSaturated the soil under water 4 days

44--Determine CBR in soaked conditionDetermine CBR in soaked condition

CBR=CBR= %100..standard

..×

load unit

load unit Test



24

BEARING RATIO TEST (CBR)

Project: Pochentong Airport Job No.

Location of Project: Pochentong Airport Boring No 2 Sample No.2

Description 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 0

1.00 0.045 2.3077

2.00 0.075 3.8462

3.00 0.11 5.641

4.00 0.145 7.4359

5.00 0.175 8.9744

6.00 0.21 10.769

7.00 0.25 12.821

8.00 0.28 14.359

9.00 0.31 15.897

10.00 0.34 17.436

CBR(2.54)= 7.1429

Acceppted CBR= 7.14

Final water Top 7.9

conten, w% Midle 7.8

(soaked) Bottom 7.99

sample 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)

L o a d ( k g f / c m

2 )

P2.54

Penetration(mm)Penetration(mm) Standard unitStandard unitload(Mpa)load(Mpa)

2.52.5 6.96.9

55 10.310.3

7.57.5 1313

1010 1616

12.712.7 1818



25

CBR equipmentCBR equipment

CBR equipmentCBR equipment



26

CBR special for field controlCBR special for field control

Compaction the soils in optimum state withCompaction the soils in optimum state withdifferent energydifferent energy

11--Compaction 10 blows per layer and saturatedCompaction 10 blows per layer and saturatedthe soil under water during 4 daysthe soil under water during 4 days



44--Determine CBR in soaked condition for eachDetermine CBR in soaked condition for each

55--Plotted values CBR with dry density on chartPlotted values CBR with dry density on chart

CBR chartCBR chart



27

CBR CBR GeneralGeneralratingrating

UsesUses Classification systemClassification system

USCSUSCS AASHTO AASHTO

00--33 Very poor Very poor SubgradeSubgrade OH,CH,MH,CLOH,CH,MH,CL A5,A6,A7 A5,A6,A7

33--77 Poor toPoor tofairfair

SubgradeSubgrade OH,CH,MH,OLOH,CH,MH,OL A4,A5,A6,A7 A4,A5,A6,A7

77--2020 FairFair SubbaseSubbase OL,CL,ML,SC,OL,CL,ML,SC,

SM,SPSM,SP

A2,A4,A6,A7 A2,A4,A6,A7

2020--5050 GoodGood BaseBase

subbasesubbase

GM,GC,SW,GM,GC,SW,

SM,SP,GPSM,SP,GP

A1b,A2 A1b,A2--5,5, A3,A2 A3,A2--66

>50>50 ExcellentExcellent BaseBase GW,GMGW,GM A1 A1--a,A2a,A2--44

A3 A3

Control soils compactionControl soils compaction

%Compaction=%Compaction=

Determine field density byDetermine field density by

using:using:11--Undisturbed samplingUndisturbed sampling

22--Sand cone methodSand cone method

33--Balloon density equipmentBalloon density equipment

44--Nuclear methodNuclear method

max

. %100

d

field d

ρ

ρ ×



28

Sand cone methodSand cone method

Control CBR Control CBR Field CBR Field CBR By using Dynamic cone penetration test DCPBy using Dynamic cone penetration test DCP

11--Kleyn and Van Heerden(60Kleyn and Van Heerden(6000cone) : Lg.(CBR)=2.632cone) : Lg.(CBR)=2.632--1.28Lg.(mm/blow)1.28Lg.(mm/blow)

22--Smith and Pratt (30Smith and Pratt (3000cone) : Lg.(CBR)=2.555cone) : Lg.(CBR)=2.555--1.145Lg.(mm/blow)1.145Lg.(mm/blow)

33--VanVuuren (30 VanVuuren (3000 cone) : Lg.(CBR)=2.503cone) : Lg.(CBR)=2.503--1.15Lg.(mm/blow)1.15Lg.(mm/blow)

44--TRRL Road Note 8(60TRRL Road Note 8(6000cone) : Lg.(CBR)=2.48cone) : Lg.(CBR)=2.48--1.057Lg(mm/blow1.057Lg(mm/blow))

By using CBR ChartBy using CBR Chart



29

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, sofor clayey soils with permeability very low, sofor short term loading soils and water work for short term loading soils and water work together.together.

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

short term loading soils work yourself onlyshort term loading soils work yourself only

For analyze soils stability problems(bearingFor analyze soils stability problems(bearingcapacity,slope stability,lateral pressure oncapacity,slope stability,lateral pressure onearthearth--retaining structure)retaining structure)



30

MohrMohr--Coulomb CriteriaCoulomb Criteria

The shear stress on the failure plan asThe shear stress on the failure plan asa linear function of the normal stressa linear function of the normal stress(Coulomb,1776)(Coulomb,1776)

ττ == cc ++ σσ tgtgϕϕ

A material fails because of a critical A material fails because of a critical

combination of normal stress andcombination of normal stress andshear stress, and not from eithershear stress, and not from eithermaximum normal or shear stressmaximum normal or shear stressalone (Mohr,1900)alone (Mohr,1900)



31

Effective stress in soilsEffective stress in soilsmassmass

Total stressTotal stress σσ00= γ = γ sat.sat.ZZ

Effective stressEffective stress σσ’ ’ 00= γ = γ ’’..ZZ

Pore water pressure U=Pore water pressure U= γ γ ww.Z.Z

γ γ ’=’= γ γ satsat-- γ γ ww γ γ ww unit weight of waterunit weight of water

Failure planFailure planσx

τ

σy

τ

σ

τf

θ

θ= 45+φ/2



32

MohrMohr--Coulomb failure criteriaCoulomb failure criteriaτ

σC

φ

Line Coulomb’s: τ = σ.tgφ+C

Unconfined compression testUnconfined compression test

Type TSA testType TSA test

Undisturbed sample withUndisturbed sample withhh00=2d=2doo

SpeedSpeed εε=2%/min=2%/min

εε=2%/min==2%/min=∆∆h/hh/h00*100%/min*100%/min

For determine undrainedFor determine undrainedcohesion Cu, in this casecohesion Cu, in this caseφφu=0u=0



33

qu

Mohr circleMohr circle

τ

σ0 qu

Cu



34

Direct shear testDirect shear test Type undrainedType undrained

test or drainedtest or drainedtesttest

UndisturbedUndisturbedsamplesample

For determineFor determinecohesion of soilscohesion of soils

CC and internaland internalfriction angle of friction angle of soilssoils φφφφφφφφ

Build byBuild byCasagrandeCasagrande

Shear boxShear box

Porous

stone

Shear force

Shear box

Normal force

Porous

stone

Loading plate

τ

τ

Soil sample



35

Determine C & Determine C & φφφφφφφφ

( )22

)(

ii

iiii

n

ntg

σ σ

σ τ σ τ φ

∑−∑

∑∑−∑=

n

tgC ii σ φ τ ∑−∑

=

τ

σ

C

φ

0

Triaxial testTriaxial test

UU test: Unconsolidated undrainedUU test: Unconsolidated undrainedtesttest

CU test: Consolidated undrained testCU test: Consolidated undrained test

CD test: Consolidated drained testCD test: Consolidated drained test



36

Triaxial equipmentTriaxial equipment



37

UU testUU test

τ

σ0 σ0 qu

Cu

General relationship of consistency andGeneral relationship of consistency andunconfined compression strength of clayunconfined compression strength of clay

ConsistencyConsistency qquu(KN/m(KN/m22))

Very soft Very soft 0 0--2525

SoftSoft 2525--5050Medium stiff Medium stiff 5050--100100

Stiff Stiff 100100--200200

Very stiff Very stiff 200200--400400

hardhard >400>400



38

Empirical equation related to Cu andEmpirical equation related to Cu and σσσσσσσσ’’00

ReferenceReference RelationshipRelationship RemarksRemarks

SkemptonSkempton(1957)(1957)

Cu=[0.11+0.0037.ICu=[0.11+0.0037.IPP].].σσ’ ’ 00Cu from vane shear testCu from vane shear test

For normallyFor normallyconsolidated clayconsolidated clay

Chandler(1988)Chandler(1988) Cu=[0.11+0.0037.ICu=[0.11+0.0037.IPP].].σσ’ ’ ccCu from vane shear testCu from vane shear test

σσ’ ’ cc preconsolidationpreconsolidation

pressurepressure

Can be use forCan be use forover consolidatedover consolidatedclay not valid forclay not valid forsensitive claysensitive clay

Jamiolkowski etJamiolkowski etal (1985)al (1985)

Cu=[0.23 0.04].Cu=[0.23 0.04].σσ’ ’ cc For lightly overFor lightly overconsolidated clayconsolidated clay

±

CU & CD testCU & CD testτ

σ0

φ

Cσ3 σ1



39

Typical values of drained Angle of Typical values of drained Angle of

friction for Sand and Siltfriction for Sand and SiltSoil typeSoil type ΦΦ (degree)(degree)

Sand : Rounded grainsSand : Rounded grains

LooseLoose 2727--3030

Medium denseMedium dense 3030--3535

DenseDense 3535--3838

Sand : Angular grainsSand : Angular grains

LooseLoose 3030--3535

Medium denseMedium dense 3535--4040

DenseDense 4040--4545

Gravel with some sandGravel with some sand 3434--4848

SiltsSilts 2626--3535

Typical values of drained Angle of Typical values of drained Angle of friction and Cohesion for Gravelfriction and Cohesion for Gravel

USCSUSCS Φ(Φ(degree)degree) C(KN/mC(KN/m22))

GWGW 40 540 5 00

GPGP 38 638 6 00

GMGM 36 436 4 00GCGC 34 434 4 00

GMGM--MLML 35 535 5 00

GMGM--GCGC 33 333 3 2 22 2

GCGC--CLCL 29 429 4 3 33 3

GCGC--CHCH 28 428 4 4 44 4

±

±

±±

±

± ±

± ±

± ±



40

Typical values of drained Angle of Typical values of drained Angle of

friction and Cohesion for Sandfriction and Cohesion for SandUSCSUSCS Φ(Φ(degree)degree) C(KN/mC(KN/m22))

SWSW 38 538 5 00

SPSP 36 636 6 00

SMSM 34 334 3 00

SCSC 32 432 4 00

SMSM--MLML 34 334 3 00

SMSM--SCSC 31 331 3 5 55 5

SCSC--CLCL 28 428 4 5 55 5

SCSC--CHCH 27 327 3 10 1010 10

±

±

±

±

±

± ±

± ±

± ±

Typ ca va ues o ra ne Ang e oTyp ca va ues o ra ne Ang e ofriction and Cohesion for Fine grainedfriction and Cohesion for Fine grainedsoilssoils

USCSUSCS Φ(Φ(degree)degree) C(KN/mC(KN/m22))

MLML 33 433 4 00

CLCL--MLML 30 430 4 15 1015 10

CLCL 27 427 4 20 1020 10

CHCH 22 422 4 25 1025 10

OLOL 25 425 4 10 510 5

OHOH 22 422 4 10 510 5

MHMH 24 624 6 5 55 5

±

±

±

±

±

±

±±

±

±

±

±

±



41

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 mass

11--Stress at the center of footingStress at the center of footing

σσvMvM=4.I=4.I22.q = 4.K.q.q = 4.K.q

BL

Qq =

+−+

+++

++

++

+++

++=

1

12

1

2

1

12

4

12222

22

22

22

2222

22

2nmnm

nmmnarctg

nm

nm

nmnm

nmmn I

π

Z

Bm

2

=

Z

Ln

2

=

a

Z =ξ



42

Determine stress in soils massDetermine stress in soils mass

22--Stress at the corner of footingStress at the corner of footing

σσvM1vM1=I=I22.q = K.q.q = K.q

BL

Qq =

+−+

+++

++

++

+++

++=

1

12

1

2

1

12

4

12222

22

22

22

2222

22

2

nmnm

nmmnarctg

nm

nm

nmnm

nmmn I

π

Z

Bm =

Z

Ln =

a

Z

2=ξ

e erm ne s ress n so masse erm ne s ress n so massby 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

ξ

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



43

ConsolidationConsolidation

Settlement of soilsSettlement of soils

∆hi

S

Ho

S

ho

Before loading After loading



44

Consolidation curveConsolidation curve

e

Logσ

σ’pσ1 σ2 σ3 σ4

e1

e2

e3

e4

Determination parameter of Determination parameter of consolidationconsolidation

Natural void ratioNatural void ratio

Void ratio after consolidation Void ratio after consolidation

Swell indexSwell index

Compression indexCompression index

0

00

H

H he

−=

0

00

H

h H he ii

∆−−=

12

21

loglog σ σ −

−=

eeC s

34

43

loglog σ σ −

−=

eeC c



45

Determination parameter of Determination parameter of

consolidationconsolidation

Modulus of elasticityModulus of elasticity

ee andand σσσσσσσσ located between 100 Kpa to 200KPalocated between 100 Kpa to 200KPa

Compression indexCompression index

Swell indexSwell index

σ β ∆∆−

+=

e

em E k s

01.

Types of soil emKuNsMBaF mk GaRs½yeTAnw gemKuNes<at eo

0.45 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



46

Soil type RbePTdI µ β

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 soilsElastic parameter of various soils

Type of soilsType of soils Modulus of Modulus of elasticity Es(Mpa)elasticity Es(Mpa)

Poisson’s ratioPoisson’s ratio µµss

Loose sandLoose sand 1010--2525 0.200.20--0.400.40

Medium denseMedium densesandsand

1515--3030 0.250.25--0.400.40

Dense sandDense sand 3535--5555 0.300.30--0.450.45

Silty sandSilty sand 1010--2020 0.200.20--0.400.40

Sand and gravelSand and gravel 7070--170170 0.150.15--0.350.35

Soft claySoft clay 44--2020

0.200.20--0.500.50Medium stiff clayMedium stiff clay 2020--4040



47

Coefficient of consolidationCoefficient of consolidation

Log t

∆∆∆∆h

t1

t1 /4

t 100

δ100

δ0

δ50

t 501min

Determination coefficient of consolidationDetermination coefficient of consolidation

Coefficient of consolidation from CasagrandeCoefficient of consolidation from Casagrandemethod Cmethod Cvv[m[m

22 /s] /s]

hh00-- initial thickness of sampleinitial thickness of sample

Permeability coefficientPermeability coefficient

Coefficient of compressibilityCoefficient of compressibility

Coefficient of volume changeCoefficient of volume change

50

2

197.0t

H C v =

2

500 δ −=h

H

eaC K wvv

+=

1.. γ

σ ∆

∆−=

ea v

01 e

am v

v+

=



48

Typical values of coefficientTypical values of coefficient

of consolidation Cof consolidation Cvv[cm[cm22/s]/s]

Liquid limitLiquid limit Lower limit of Lower limit of recompressionrecompression

UndisturbedUndisturbedvirginvirgin

compressioncompression

Upper limitUpper limitremoldedremolded

3030 3.5*103.5*10--22 5*105*10--33 1.2*101.2*10--33

6060 3.5*103.5*10--33 1*101*10--33 3*103*10--44

100100 4*104*10--44 2*102*10--44 1*101*10--44

Source U.S Navy 1962

In situ testIn situ test

Static cone penetration testStatic cone penetration test

Dynamic cone penetration test DCPDynamic cone penetration test DCP

Standard penetration testStandard penetration test

Shear vane testShear vane test

Pocked penetration testPocked penetration test



49

Static cone penetration testStatic cone penetration test

K

c

N

qCu 0σ −

=

+=

0'log38.01.0

σ φ c

q Arctg

E=2.qc

qc:cone resistance

Nk=20

Dynamic cone penetration testDynamic cone penetration test

A

H M

M M e

M qd

..

)'.( +=

qd :cone resistance

M:weight of hammer

M’:weight of rods

A:cone area

H:height hammer falling

e:penetration for one blow



50

Standard penetration testStandard penetration test

Index SPTIndex SPT

N value is amount of blows for penetration split spoon sampler

in soils 30 cm

N=N1+N2

Ncor= CN.Nfield

CN = 0.77log D.

2000

γ Peck1974

0'

178.9

σ = N C Liao & Whihman 1986

0'01.01

2

σ += N C Skempton1986

−=

6.95

'log25.11 0σ

N C Seed 1975

For fine sand or silt saturated with N >15

Ncor=15+0.5 (Nfield-15)



51

Relationship of SPT and propertiesRelationship of SPT and properties

mechanics of soilsmechanics of soils2020 += N φ Hatanaka & Uchida 1996200054.03.01.27 N N −+=φ Wolff 1989

1518 += N φ For road and Bridges design sMrab;fñ ;l;nigs <an

2736.0 += N φ For building design sMrab; GaKar

2045.0 += N φ in general sMrab;krNITUeTA

E (KPa) = 766N For sand saturated sMrab;xSac;CaMTw k

E (KPa) = 500(N+15) For dense sand sMrab; xSac;hab;

E (KPa) = 2600N For dense sand sMrab; xSac;hab; E (KPa) = 600(N+6) For Gravelly sand (N<15) sMrab; RKYslayxSac;

E (KPa) = 600(N+6) +2000 For Gravelly sand (N>15) sMrab; RKYslayxSac;

E (KPa) = 320(N+15) For Clayey Sand sMrab; xSac; laydI\dæ

E (KPa) = 300(N+6) For Silt,sandy silt,clayey silt sMrab; dIl,aym:dæ

Relationship of SPT and propertiesRelationship of SPT and propertiesmechanics 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 K=4.4KPa3.5KPa <K <6KPa in general we take K=4.4KPa

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



Thank you for yourThank you for your

attentionattention

Mr. Sieng PEOUMr. Sieng PEOU

Master science of Master science of geotechnicalgeotechnicalengineeringengineering

advance soil mechanics [compatibility mode]

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