Correlating, Vs, qc and Cyclic Resistance of a Silty Sand through

Laboratory Calibration Tests

An-Bin Huang, Yao-Tao Huang, and Yu-Chen KuoDepartment of Civil Engineering National Chiao Tung University Hsin Chu, TAIWAN

Effects of nonplastic fines on CRR

Higher CRR ? Lower CRR ? Depends… ?

Effects of nonplastic fines on qc

Variation of qc under the same void ratio and stress conditions as the fines content changes ?

What void ratio ?

Seed and de Alba (1986)

0 1 0 2 0 3 0 4 0 5 0F in es co n ten t, %

0

1 0

2 0

3 0

4 0

5 0

qcl

N

B ase d o n re s id u a l s tren g th (Ish ih a ra e t a l., 1 9 9 1 )B ase d o n c y c lic s tre n g th (S e ed & D e A lb a , 1 9 8 6 )

Ishihara (1993)

0 1 0 2 0 3 0 4 0 5 0F in e s co n te n t, %

0

2 0

4 0

6 0

8 0

1 0 0

qcl

N

R e co m m e n d e d fo r d es ig n

(S ta rk a n d O lso n , 1 9 9 5 )

S ee d a n d D e A lb a (1 9 8 6 )

Stark and Olson (1995)

Effects of nonplastic fines on Vs

Variation of Vs under the same void ratio and stress conditions as the fines content changes ?

What void ratio ?

Andrus and Stokoe (2000)

Youd et al. (2001)

…The CRR corrections based on fines contents should be used with engineering judgment and caution…

Liquefaction potential mapping

qc Vs

Laboratory calibration tests

CPT calibration tests Vs measurements with bender elemen

ts Cyclic triaxial tests Use Mai Liao Sand (MLS), a typical silt

y fine sand in Central Western Taiwan

1 .0 0 0 0 .1 0 0 0 .0 1 0 0 .0 0 1S iev e o p e n in g , m m

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

Perc

ent f

iner

, %

H y d ro m e te r te s tS iev e an a ly sis

Coarse grains Fine grains

10 1 00 1 0 00 1 0 0 00 1 0 0 0 00log p' , kP a

0 .5

0 .6

0 .7

0 .8

0 .9

1 .0

Voi

d ra

tio ,

e

Y a m am u ro et a l. ( 1 99 6 )

M L SIn itia l D r = 2 4 %

I nitia l D r = 3 8 %

I nitia l D r = 6 2 %

Q u ar tz sa ndL o o se

M e d ium

CPT calibration tests in MLS

FC = 0%, 15%, 30% and 50% Dro = 50%, 70% and 85% ’v = 100, 200 and 300 kPa K = 0.5, 1 and 2

The calibration chamber

Sample preparation

Dry deposition Saturated under a backpressure or dry Stresses applied in steps follow the

designated K value

0 1 2 3 4 5q c, M P a

0 1 2 3q c, M P a

0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

Dep

th o

f pen

etra

tion,

mm

0 5 1 0 1 5 2 0q c , M P a

F C = 1 5 % d ry (9 7 -0 5 0 1 -D -H ) sa t. (9 7 -0 1 2 0 -S -S )

F C = 3 0 % d ry (9 9 -1 0 2 3 -D -H ) sa t. (9 8 -0 1 2 2 -S -S )

F C = 5 0 % d ry (0 0 -0 5 1 7 -D -S ) sa t. (9 9 -1 2 3 0 -S -S )

0 1 0 0 2 0 0 3 0 0(q c-p )/p '

0 .4

0 .6

0 .8

1 .0

1 .2

0 .5

0 .7

0 .9

1 .1

e c

T ic in o (A lm eid a e t a l., 1 9 9 1 )Q u iou (A lm eid a e t a l., 1 9 9 1 )M L S , F C = 0%M L S , F C = 15 %M L S , F C = 30 %M L S , F C = 50 %

c

C

a

h

C

a

v

a

c eCPP

CPq

30

2

exp21

21

2

230 exp

CC

v

a

a

cc

C PPq

eCKC

Ncq 1 = cC eCKC 30 exp2

n = C1+C2

Fines content

C0 C1 C2 C3

% n = C1+C2

0 383 0.03 0.42 -2.02 0.9415 236 0.23 0.44 -1.63 0.9630* 26 0.02 0.77 -1.04 0.95

50+ 316 0.69 0.11 -6.05

0.93

0 5 1 0 1 5 2 0 2 5 3 0

M easu red q c, M P a

0

5

1 0

1 5

2 0

2 5

3 0

Com

pute

d q c

, MPa

F C , %01 53 05 0

0 1 0 2 0 3 0 4 0 5 0F in es co n te n t, %

0

1

2

3

4

Soil

beha

viou

r typ

e in

dex,

I C

Z o n e 2 : o rg a n ic so ils -p ea ts

Z o n e 3 : c lay to s ilty c la y

Z o n e 4 : c la y e y s ilt to s ilty c la y

Z o n e 5 : s ilty sa n d to sa n d y s ilt

Z o n e 6 : c lea n san d to s ilty sa n d

Z o n e 7 : sa n d to g ra v e lly san d

R ec o m m en d e d g en e ra l c o rre la tio n

Effects of fines on in MLScrefc qq

Reference state ofdensity

FC%

K=0.5 K=1.0

0.5 1.0 2.0 0.5 1.0 2.0

ec=0.6715 0.68 0.79 0.91 0.68 0.79 0.9230 0.08 0.10 0.13 0.10 0.13 0.1650 -- -- -- 0.04 0.06 0.07

ec = 0.73~79

15 0.78 0.91 1.05 0.79 0.92 1.0630 -- -- -- -- -- --50 -- -- -- -- -- --

ec =0.9515 1.21 1.41 1.63 1.22 1.42 1.6530 -- -- -- -- -- --

av P av P

Cyclic triaxial tests

Sample preparation by wet tamping in 4 layers

K = 1 Saturated under a back pressure ’v = 100 kPa Bender element Vs measurement on th

e same triaxial specimen

1 1 0 1 0 0 1 0 0 0N v a lu e

0 .1

0 .2

0 .3

0 .4

0 .5

0 .6

CR

R

F C ,% ec C R R0 0 .9 7 0 .1 90 0 .9 3 0 .2 20 0 .8 5 0 .3 50 0 .8 0 0 .4 50 0 .7 3 0 .5 41 5 0 .7 3 0 .4 51 5 0 .8 0 0 .3 43 0 0 .8 1 0 .1 63 0 0 .7 3 0 .2 2

1 2 0 1 4 0 1 6 0 1 8 0 2 0 0V s, m /s

0 .7

0 .7 5

0 .8

0 .8 5

0 .9

0 .9 5

e c

F C , % 'c , k P a

0 1 0 01 5 1 0 03 0 1 0 0

0 .6 0 .7 0 .8 0 .9V o id R a tio , e

8

1 2

1 6

2 0

2 4

2 8

(K2) m

ax

F C < 5 %F C = 1 5 %F C = 3 0 %F C = 5 0 %

0 5 0 1 0 0 1 5 0 2 0 0q c 1 N

0

0 .1

0 .2

0 .3

0 .4

0 .5

0 .6

Cyc

lic st

ress

or r

esis

tanc

e ra

tio, C

SR o

r CR

RC

RR L a b . c o rre la tio n

F C , %01 53 0

C le a n sa n d R o b e rtso n a n d W rid e (1 9 9 8 )

P ro je c te d c le a n M L SF C = 0 to 1 5 %

Tentative due to differences in sample preparation methods

0 1 0 2 0 3 0 4 0 5 0F in es c o n ten t, %

0

1 0

2 0

3 0

4 0

5 0

6 0

qcl

N

B ased o n re s id u a l s tren g th (Ish ih a ra e t a l., 1 9 9 1 )B ased o n cy c lic s tre n g th (S eed & D e A lb a , 1 9 8 6 )M L S ca lib ra tio n

0 1 0 2 0 3 0 4 0 5 0F in e s co n te n t, %

0

2 0

4 0

6 0

8 0

1 0 0

qcl

N

M L S c a lib ra tio n

R e c o m m e n d e d fo r d es ig n

(S ta rk a n d O lso n , 1 9 9 5 )

S e ed a n d D e A lb a (1 9 8 6 )

0 1 0 0 2 0 0 3 0 0S h ea r w a v e v e lo c ity , V s1 , m /s

0

0 .1

0 .2

0 .3

0 .4

0 .5

0 .6

Cyc

lic s

tress

or r

esis

tanc

e ra

tio, C

SR o

r CR

R

L a b . c o rre la tio n F C , %

01 53 0

3 52 0

5

A n d ru s an d S to k o e , 2 0 0 0

F C , %

Concluding remarks

The current qc and Vs methods too conservative? Not necessarily, due to differences in Shearing mode K values

Fines affect CRR and Vs through soil structure, grain characteristics and compressibility

Drainage effects are much more significant to qc

When using CPT for liquefaction potential assessment in MLS

Make adjustment based on t50 from pore pressure dissipation test or change of qc after pore pressure dissipation

But not IC