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Advance Soil mechanicsAdvance Soil mechanics
Present by Mr. Sieng Present by Mr. Sieng PEOUPEOU
Master 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.
..
weighttotal
cumulativeretainedweight
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*%SW
RRaP
T
LKD
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 : Outside diameter of the sampling tubetube
•DDii:Inside diameter of the sampling tube:Inside diameter of the sampling tube
100(%)2
220
i
iR D
DDA
Soils unit weightSoils unit weight
Natural 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
e
eSG
V
W
1
s
s
V
W100
1
V
Ws
%100s
w
W
W
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
V
Ve
w
s
v
w
eV
VS
%100
Ws
sat e
eG
1
ws
wsat e
G
1
1'
Another parametersAnother parameters
Specific gravity:
Relative density:
Saturated water content:
ws
ss V
WG
%100minmax
max
ee
eeDR
%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(%)(%) DescriptionDescription
0 to 150 to 15 Very looseVery 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 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 soils
Plastic 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 classification
USCS: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 ca te d C L o r C HP oo rly g ra dedc laye 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 clayey
s i lty G rav e lG C -G M -G P
U C < 4O n p la stic C h a rt C asa gra nd
L o ca te d C L o r C HW ell g rad ed
c laye 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 C a sag ran de
M ixe d G rav e l5 % < % P (0 .0 75 m m )< 1 2%
GravelGravel
L o ca te d C L o r C Hc laye 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 laye 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 ca te d C L o r C HP oo rly g ra dedc laye 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 clayey
s i lty S a ndS C -S M -S P
U C < 6O n p la stic C h a rt C asa gra nd
L o ca te d C L o r C HW ell g rad edc laye 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 C a sag ran de
M ixe d S a nd5 % < % P (0 .0 75 m m )< 1 2%
SandSand
L o ca te d C L or CHc laye y S a nd
S C
L o ca te d M L or 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 ve 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 ve llyF a t C lay
% S > 1 5%G ra ve llyF a t C lay
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%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
I f% 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 sa 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 ith g rav e l
% S > % G
% S < 1 5%G ra ve lly
E la stic S i lt
% S > 1 5%G ra ve 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 ilty clayw ith g rav e l
% S > % G
% S < 1 5%G ra ve 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 State Highway and Transportation official, was Transportation official, was developed 1929 and proposed by developed 1929 and proposed by the committee on Materials for the committee on Materials for sub grades and Granularity Type sub grades and Granularity Type Boards of the Highway Research Boards of the Highway Research Road in 1945(ASTM Test Road in 1945(ASTM Test designation D-3282;AASHTO designation D-3282;AASHTO method M145)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 classificationclassification
A-4A-4 A-5A-5 A-6A-6 A-7A-7
A-7-5A-7-5
A-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 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)
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 152.4mm152.4mm
Volume 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 N
Height 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%%
Used soil Used soil
%P(9.5)%P(9.5)
%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 152.4mm152.4mm
Volume 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%%
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%%
Used soil Used soil
%P(9.5)%P(9.5)
%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 statestate
2-Determine CBR in dry condition2-Determine CBR in dry condition
3-Saturated the soil under water 4 3-Saturated the soil under water 4 daysdays
4-Determine CBR in soaked condition4-Determine CBR in soaked condition
CBR=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 7.9
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)
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 4-Determine CBR in soaked condition for
eacheach5-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 BaseBase
subbasesubbaseGM,GC,SW,GM,GC,SW,
SM,SP,GPSM,SP,GPA1b,A2-5, A1b,A2-5, A3,A2-6A3,A2-6
>50>50 ExcelleExcellentnt
BaseBase GW,GMGW,GM A1-a,A2-4A1-a,A2-4
A3A3
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 sandy soils with high permeability,so
for short term loading soils work yourself for short term loading soils work yourself onlyonly
•For analyze soils stability For analyze soils stability problems(bearing capacity,slope problems(bearing capacity,slope stability,lateral pressure on earth-stability,lateral pressure on earth-retaining structure)retaining 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
’’= = sat- sat- 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 box
Porous stone
Shear force
Shear box
Normal force
Porous stone
Loading plate
Soil sample
Determine C & Determine C &
22
)(
ii
iiii
n
ntg
n
tgC 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 0-250-25SoftSoft 25-5025-50
Medium stiffMedium stiff 50-10050-100StiffStiff 100-200100-200
Very stiffVery stiff 200-400200-400hardhard >400>400
Empirical equation related to Cu and Empirical equation related to Cu and ’’00ReferenceReference RelationshipRelationship RemarksRemarks
Skempton Skempton (1957)(1957)
Cu=[0.11+0.0037.ICu=[0.11+0.0037.I
PP].].’’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.I
PP].].’’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 27-3027-30
Medium denseMedium dense 30-3530-35
DenseDense 35-3835-38
Sand : Angular grainsSand : Angular grains
Loose Loose 30-3530-35
Medium denseMedium dense 35-4035-40
DenseDense 40-4540-45
Gravel with some sandGravel with some sand 34-4834-48
SiltsSilts 26-3526-35
Typical values of drained Angle of Typical values of drained Angle of friction and Cohesion for Gravelfriction and Cohesion for Gravel
USCSUSCS degree)degree) C(KN/mC(KN/m22))
GWGW 40 540 5 00
GPGP 38 638 6 00
GMGM 36 436 4 00
GCGC 34 434 4 00
GM-MLGM-ML 35 535 5 00
GM-GCGM-GC 33 333 3 2 22 2
GC-CLGC-CL 29 429 4 3 33 3
GC-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 Sand
USCSUSCS 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
SM-MLSM-ML 34 334 3 00
SM-SCSM-SC 31 331 3 5 55 5
SC-CLSC-CL 28 428 4 5 55 5
SC-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 00
CL-MLCL-ML 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
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 footing
vMvM=4.I=4.I22.q = 4.K.q.q = 4.K.q
BLQq
1
12
1
2
1
12
4
12222
22
22
22
2222
22
2 nmnm
nmmnarctg
nm
nm
nmnm
nmmnI
Z
Bm
2
Z
Ln
2
a
Z
Determine stress in soils massDetermine stress in soils mass2-Stress at the corner of footing2-Stress at the corner of footing
vM1vM1=I=I22.q = K.q.q = K.q
BLQq
1
12
1
2
1
12
4
12222
22
22
22
2222
22
2 nmnm
nmmnarctg
nm
nm
nmnm
nmmnI
Z
Bm
Z
Ln
a
Z
2
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 consolidationconsolidation
Natural void ratioNatural void ratio
Void ratio after consolidationVoid ratio after consolidation
Swell indexSwell index
Compression indexCompression index
0
00
H
Hhe
0
00
H
hHhe ii
12
21
loglog
ee
Cs
34
43
loglog
ee
Cc
Determination parameter of Determination parameter of consolidationconsolidation
Modulus of elasticityModulus of elasticity
ee and and located between 100 Kpa to 200KPalocated between 100 Kpa to 200KPa
Compression indexCompression index
Swell indexSwell index
e
emE 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 soilssoils
Type 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 0.20-0.400.20-0.40
Medium dense Medium dense sandsand
15-3015-30 0.25-0.400.25-0.40
Dense sandDense sand 35-5535-55 0.30-0.450.30-0.45
Silty sandSilty sand 10-2010-20 0.20-0.400.20-0.40
Sand and Sand and gravelgravel
70-17070-170 0.15-0.350.15-0.35
Soft claySoft clay 4-204-20
0.20-0.500.20-0.50Medium stiff Medium stiff clayclay
20-4020-40
Stiff clayStiff clay 40-10040-100
Coefficient of consolidationCoefficient of consolidation
Log t
h
t1
t1/4
t 100
t 501min
Determination coefficient of Determination coefficient of consolidationconsolidation
Coefficient of consolidation from Coefficient of consolidation from Casagrande method CCasagrande method Cvv[m[m22/s]/s]
hh00- initial thickness of sample- initial thickness of sample
Permeability coefficientPermeability coefficient
Coefficient of compressibilityCoefficient of compressibility
Coefficient of volume changeCoefficient of volume change
50
2
197.0t
HCv
2500
h
H
e
aCK wvv
1
..
e
av
01 e
am vv
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
N
qCu 0
0'log38.01.0
cqArctg
E=2.qc
qc:cone resistance
Nk=20
Dynamic cone penetration testDynamic cone penetration test
A
HM
MMe
Mqd
..
)'.(
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
0'01.01
2
NC Skempton1986
6.95
'log25.11 0
NC 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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