斯坦福大学老师课件

4540353025

20751.2 1.1 1.00.90.80.750.70.650.60.550.550.50.450.40.35

0.30.250.20.15

(G = 2.68)0.50.450.40.350.30.250.20.15

8090100110120130140150

φ` Obtained from effective stress failure envelopes approximate correlation is for cohesionless materials without plastic fines

ML SM SP SW GP GW R e l a t i v e D e n s i t y 100%i n t h i s r a n g e a n d 025%50%75%Angle of Internal Friction Vs Density (For Coarse Grained Soils)

Adapted from NA VFAC DM-7.1 (5/82) p 7.1 - 149

Correlations Of Strength Characteristics For Granular Soils

Material Type A n g l e o f I n t e r n a l F r i c t i o n φ`(D e g r e e s ) Dry Unit Weight (γD

), PCF V oid Ratio, e

Porosity, n

Coefficient of Consolidation Vs Liquid Limit

Adapted from NA VFAC DM-7.1 (1982)

3

2

10-2

10-3

10-4

Liquid Limit (LL)

(C v ), F T 2/d a y C o e f f i c i e n t o f C o n s o l i d a t i o n (C v ), C m 2/s e c 8

8

654

3

2

654

8

6543

2

210.70.50.30.20.1

0.070.050.030.020.010.0070.00520406080100120140160Undisturbed Samples:C v in Range of Virgin Compression C v in Range of Recompression Lies Above this Lower Limit Completely Remolded Samples:C v Lies Below this Upper Limit 0.40

0.350.300.250.200.150102030

405060708090U n d r a i n e d S t r e n g t h R a t i o Plasticity Index, I p (percent)

Adapted from Ladd (1991), JGE, ASCE, 117(4) Comparison of field and laboratory undrained strength ratios for nonvarved sedimentary soils (OCR = 1 for laboratory CK o U testing)

Note: C u = S u Undrained shear strength for design (stability analyses)Note: Linear Regression Lines for Clay Data ********

*

Source of Strength Data A- Line Above Below Field c u /σp : Larsson (1980)Lab CK o U τave /σvc :Table 4Lab CK o UDSS τh /σvc : MIT *c u /σp τh /σvc τave /σvc

50403020

10

00204060801002004006001000

F r

i

c

t

i

o

n

A n

g

l

e

,

φ',

D e

g

r e

e

s Plasticity Index, I p , percent

Soft and Stiff Clays, and Shale Compositions

Clay Minerals

φ

' (oc) Data from

Table 3NC Values of Friction Angle φ' for Natural Clay Compositions NC For σ

p /σn Range of 10 to 20

For σ

p /σn Range of 2 to 5

σp = 4100 kPa

c c

30002000

1000

02000400060008000

S h

e

a r

S

t

r

e s

s

,

k P

a

σn = Effective Normal Stress, kPa

φPeak Strength against Effective Normal Stress Relationship of London Clay Sample from 35 m Depth (Data from Bishop et al. 1965)

10,000

10,00

100

101

0.110100100010,000100,000

c

p σ= 0.024

10 (Table1)

10

c

p σ= 0.10

c

,

k

P

a σp , kPa

Relationship between Cohesion Intercept and Preconsolidation

Pressure

Adapted from Mesri & Adel - Ghaffar (1993), JGE, ASCE, 119(8)

2 to 5

10 to 20

n σp σin /σn Range of