part v-5 - mit opencourseware · pdf file(^^) from poulos and davis (1974), figure 5.32...
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L2
L0
0.8
0.6
0.4
0.2
00 1 2 3 4 5
Rough Surface
H B
q
pe =
0.75 ATH/B = ∞
H/B
(^) From Poulos and Davis (1974), Figure 5.2(^^) From Poulos and Davis (1974), Figure 5.32
Undrained Elastic Settlement Computation for Uniform Loading on Elastic Layer
Adapted from D`Appolonia` et al. (1971), Foot & Ladd (1981)
Note: σ'vm = σ'p & Cu = Su
Intial Settlement (p1/2)
qBEu Ip
Ip
Strip Loading(^)
Circular Loading(^^)
For Saturated SoilWith ν=0.50
2000
1000800
600
400
200
100
80
60
40
200.2 0.4 0.6 0.8
At τh/cu = 1/3 At τh/cu = 2/3
1000 500
400
300
200
100
0
800
600
400
200
01 2 4 6 8 10 1 2 4 6 8 10
EuCu
EuCu
EuCu
OCR = σ` vm vc/σ` OCR = σ` vm vc/σ`
Applied Shear Stress Ratio τh/cu(1/Factor of Safety)
Eu = 3τh/γ
Cu = (τh)max
τh = Applied Horizontal Shear Stress
γ = Shear Strain
(a) Normalized Secant Modulus vs. Stress Level for Normally Consolidated Soils
(b) Normalized Secant Modulus vs. Overconsolidation Ratio
1
1
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
2
No. Decription Cu/σv̀cPortsmouthSensitive CL Clay
Boston CL ClayLL = 41, Ip = 22
S1 > 10, LL = 35, Ip = 150.20
0.20
3 Bangkok CH ClayLL = 65, Ip = 41 0.27
4Mane OrganicCH - CH ClayLL = 65, Ip = 38
0.285
5 AGS CH ClayLL = 71, Ip = 40 0.255
6AtchafalayaCH ClayLL = 95, Ip = 75
0.24
7 Taylor River PeatWN = 500 %
From Ladd & Edgers (1972)
MIT for Dames & MooreMIT for Haley & Aldrich
0.46
1.0
0.8
0.6
0.4
0.2
S R = Ρ e
/Ρ l
H/B = 0.5
Applied Stress Ratio, q/qu
.25
f = .75
.5
0
00 0.2 0.4 0.6 0.8 1.0
1.0
0.8
0.6
0.4
0.2
S R = Ρ e
/Ρ l
H/B = 1.0
Applied Stress Ratio, q/qu
.25
f = .75
.5
0
00 0.2 0.4 0.6 0.8 1.0
1.0
0.8
0.6
0.4
0.2
S R = Ρ e
/Ρ l
H/B = 1.5
Applied Stress Ratio, q/qu
Relationship between settlement ratio and applied stress ratiofor strip foundation on homogenous isotropic elastic layer.
.25
-.25
f = .75
.5
0
00 0.2 0.4 0.6 0.8 1.0
High IP
0.8
0.6
0.4
0.2
-0.2
0
1 2 4 6 8 10
Low IP
Note : All Data for Unloading From σ'vm
Note : cu = 0.5(σ1 - σ2)f from CKoU Triaxial or Plane Strain Tests, Ko from Brooker and Ireland (1965) for ME. Organic Clay.
OCR = σ'vm vc/σ'
(1 -
K o) vo
2cu
/σ'
f =
Soil Source
MITSkempton &
Sowa(^)
MIT
MITDames &Moore(^^)
Ip(%)
21
24
30 (bulk)
38
41 AIT & MIT
40
Boston Blue Clay
Weald Clay
Varved Clay
Me Organic Clay
Bangkok Clay
AGS CH Clay
(^) 1963 (^^) 1975
Intial Settlement (p 2/2)
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