effect of lateral stress on the liquefaction resistance of scp...

R.P. OrenseUniversity of Auckland

K. Harada & J. MukaiFudo Tetra Corporation, Tokyo, Japan

K. IshiharaChuo University, Tokyo, Japan

Effect of lateral stress on the liquefaction resistance of SCP-improved sandy soils

http://www2.chuo-u.ac.jp/global/index.htmlhttp://www.auckland.ac.nz/

Mechanism of compaction

1. INTRODUCTION

enlarging

diameter

Sand Pile

compactioncompaction

pulling out redrive

Procedure

Vibratory sand

compaction pile method

Non-vibratory sand

compaction pile method

• Countermeasure against liquefaction

(by densification)

-10

-8

-6

-4

-2

0

2

4

6

0 100 200 300

(a) qt (kgf/cm 2)

DL (m)

Pre C PT

Post C PT

Depth

(m

)

SPT N-value

Post SPT

(SCP)

Post SPT

(NvSCP)

Pre SPT

Pre CPT

(SCP)

Post SPT

(SCP)

CPT qc-value (kPa×100)

Measured point

2. BACKGROUND

• Increase in penetration

resistance is due to increase in

density AND increase in lateral

stress

• How to incorporate the effect of

lateral stress?

vhcK '/' Lateral

Stress Ratio:

①Penetration　Resistances, N

1 or qc

1

～ Relative Density, Dr

(Kc=0.5)

②

Cyclic Strength, Rl

～ Relative Density, Dr

(Kc=0.5)

③　　　　　●Kc effect on N

1/qc

1 and Rl)

　　　　　　　　　　　Kc ⇒　N1 or qc1

　　　　　　　　　　　Kc ⇒ Rl

④

N1 or qc

1 ～ Rl

(Kc≧0.5)

chamber test

chamber test

cyclic torsional test

Rl～N1/qc

1

(Kc=0.5:CODE)

3. BASIC METHODOLOGY

Relation between Rl and N1(qc1) through DrRl

3

2

1RlH

3

2

1RlL

N1(qc1)H

N1 or qc1

Kc

High

Kc

High

Rl

3

2

1

RlH

3

2

1

RlL

3

2

1

3

2

1

N1(qc1)L

Kc

High

Kc

High

N1(qc1)H

N1 or qc1

N1(qc1)L

Dr

Rl

3

2

1RlH

3

2

1RlL

N1(qc1)H

N1 or qc1

Kc

High

Kc

High

Rl

3

2

1

RlH

3

2

1

RlL

3

2

1

3

2

1

N1(qc1)L

Kc

High

Kc

High

N1(qc1)H

N1 or qc1

N1(qc1)L

Dr

④

③②

①

③

Flow of Study

0.0 0.2 0.4 0.6 0.8 1.00

20

40

60

(a)

Fine sand

Coarse sand

SP

T (

N1) 8

0-v

alu

e

Dr2

4. PENETRATION RESISTANCE & REL. DENSITY

① Penetration resistance (N1)80 ～ Relative density Dr (Kc=0.5)

0.0 0.2 0.4 0.6 0.8 1.00

20

40

60

80

100

Fine Coarse

Toyoura(sat.) Harada et al.,2000 Tonegawa(sat.) Yoshida et al.

Toyoura(dry) Yasuda et al.,1995 ,1988

Fine(sat.) Gibbs-Holtz,1957 Coarse(sat.) Gibbs-Holtz,1957

Yanase*(sat.) Fujita,1968 Niigata(wet) Fujita,1968

Yanase*(wet) Fujita,1968 * quoted by Fujita,1968

Fine Coarse

Toyoura(sat.) Harada et al.,2000 Tonegawa(sat.) Yoshida et al.,1988

Toyoura(dry) Yasuda et al.,1995 Coarse(sat.) Gibbs-Holtz,1957

Fine(sat.) Gibbs-Holtz,1957 Niigata(wet) Fujita,1968

Yanase*(sat.) Fujita,1968

Yanase*(wet) Fujita,1968

* quoted by Fujita, 1968

CD=27.5

CD=35.5

Fine sand(b)

CD=9/(e

max-e

min)

1.7

Coarse sand

CD=

(N1) 8

0/D

r2

emax

-emin

From chamber tests:S

PT

(N

1) 8

0valu

e

Relation for soils tested:

CD=

(N1) 8

0/D

r2

2

7.1

50

2

7.1

minmax

2

801

06.023.0

99rrrD D

D

Dee

DCN

emax - eminDr2

4. PENETRATION RESISTANCE & REL. DENSITY

② Penetration resistance qc1 ～ Relative density Dr (Kc=0.5)

0.0 0.2 0.4 0.6 0.8 1.00

10

20

30 (a)

Fine sand

Coarse sand

CP

T q

c1-v

alu

e (

MP

a)

Dr2

0.0 0.2 0.4 0.6 0.8 1.00

20

40

60

Fine Coarse

Toyoura TUS* Da Nang(Huang et al.,2005)

Quiton** Hukksund(Jamiolkowski et. al.

Hilton(Jamiolkowski et al.,1988) ,1988)

* Tokyo University of Science Ticino(Jamiolkowski et al.,1988)

** Provided by Prosti Edgar(Jamiolkowski et al.,1988)

CDq

=12/(emax

-emin

)0.8

(b) Fine sandCoarse sand

CD

q=

qc

1/D

r2

emax

-emin

From chamber tests:

CP

T q

c1

valu

e

CD=

(qc

1)

/Dr2

Relation for soils tested:

2

8.0

50

2

8.0

minmax

2

1

06.023.0

1212rrrDqc D

D

Dee

DCq

emax - emin

Dr2

5. CYCLIC STRENGTH & REL. DENSITY

14for)14(106.17.1/0882.0

14for7.1/0882.0

801

5.4

801

6

801

801801

NNN

NNR

① SPT: Cyclic strength Rl ～ Relative density Dr (Kc=0.5)

In Japan, based on cyclic triaxial tests on

undisturbed samples (JRA, 1996)

200

1

4510

50

13534

1

65.0

1

65.0 2601

601

601 N

N

N

CRRR

In North America, based on field

observations (Youd and Idriss, 2001)

0 50 1000.0

0.2

0.4

0.6

0.8

(a)

From N1-R

l relation inJapan, Eq. (4)

Coarse sand

Fine sand

Fine sand emax

-emin

=0.450

Coarse sand emax

-emin

=0.375

Relative density, Dr (%)

Cyclic

str

eng

th, R

l

(4)

(5)

5. CYCLIC STRENGTH & REL. DENSITY

② CPT: Cyclic strength Rl ～ Relative density Dr (Kc=0.5)

In Japan, based on studies by Suzuki

and Tokimatsu (2003)

In North America, based on studies by

Robertson and Wride (1998)

MPa0.20

MPa0.22.0341.0where

7.83

16

100

1657.045.0

65.0

1

'65.0

1

1

10929.034.1

194.1

14

c

ccI

ccc

cc

o

q

qqIN

NNR

MPa3.158.4for123.01063.1

MPa8.4for077.00134.0

65.0 13

1

4

11

cc

cc

qq

qqCRRR

(7)

(6)

0 50 1000.0

0.2

0.4

0.6

0.8

(b)

From qC1

-Rl relation in

North America, Eq. (7)

Coarse sand

Fine sand

Fine sand emax

-emin

=0.450

Coarse sand emax

-emin

=0.375


Cyclic

str

eng

th, R

l

6. PENETRATION RESISTANCE & KC-VALUE

① Effect of Kc on SPT N1-value

rD

NCC

C

Kc

KcSPH

K

K

N

NC

75.080.0

,5.01

1

)(

)(

0 50 1000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Kc=0.5

(Kc/0.5)0.8-0.75Dr

Kc=1.5(a)

Kc=1.0

(N1)

Kc=1.0/(N

1)

Kc=0.5 (Harada et al.,2000)

(N1)

Kc=1.5/(N

1)

Kc=0.5 (Harada et al.,2000)


CS

PH=

(N1) K

c/(

N1) K

c=

0.5

0 50 1000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Kc=0.5

Kc=1.5Kc=1.5

Kc=1.0Kc=1.0

(b)

(Kc/0.5)07759-0.5208Dr

(Kc/0.5)0.6-0.55Dr

(qc1)

Kc=1.0/(qc

1)

Kc=0.5 (TUS*)

(qc1)

Kc=1.0/(qc

1)

Kc=0.5 (Huang et al.,2005)

(qc1)

Kc=1.5/(qc

1)

Kc=0.5 (TUS*)

(qc1)

Kc=1.5/(qc

1)

Kc=0.5 (Huang et al.,2005)

* Tokyo University of Sciense


CC

PH=

(qc1) K

c/(

qc1) K

c=

0.5

rD

NCC

C

Kcc

KccCPH

K

K

q

qC

55.060.0

,5.01

1

)(

)(

② Effect of Kc on qc1-value

CS

PH

CC

PH

7. LIQUEFACTION STRENGTH & KC-VALUE

Based on studies by Ishihara and Takatsu (1979)

NCC

C

NC K

K

R

R

,, 21

21

0 50 1000.0

0.2

0.4

0.6

0.8

Kc=0.5

(a)

From N1-R

l relation

in Japan, Eq. (4)

Kc=1.0

Kc=1.5

Average sand

emax

-emin

=0.413


Cyclic

str

en

gth

, R

l

0 50 1000.0

0.2

0.4

0.6

0.8

Kc=0.5

(b)

From qC1

-Rl relation

in North America, Eq. (7)

Kc=1.0

Kc=1.5

Average sand

emax

-emin

=0.413


Cyclic

str

en

gth

, R

l

Effect of Kc on Liquefaction Strength

From Eqtn (4) From Eqtn (7)

8. RECOMMENDED CHARTS

0 5 10 15 20 25 30 350.0

0.2

0.4

0.6

0.8

(a)

Cyclic

str

eng

th, R

l

Kc=0.5

Kc=1.0

Kc=1.5

JRA (1996)

(Kc=0.5)

SPT(N1)

80-value

0 5 10 15 20 25 30 35 400.0

0.2

0.4

0.6

0.8

Kc=1.5

(b)

Cyclic

str

en

gth

, R

l

Kc=0.5

Kc=1.0

JRA (1996)

(Kc=0.5)

Youd et al. (2001)

(Kc=0.5)

SPT(N1)

60-value

SPT N1-value and liquefaction strength

0 5 10 15 20 250.0

0.2

0.4

0.6

0.8

(a)

C1

AIJ(2001)

(Kc=0.5)

Kc=0.5

Kc=1.0

Kc=1.5

Cyclic

str

eng

th, R

l

q -value(MPa)

0 5 10 15 20 250.0

0.2

0.4

0.6

0.8

(b)

C1

Robertson et al.(1998)

(Kc=0.5)

AIJ(2001)

(Kc=0.5)Kc=0.5

Kc=1.0

Kc=1.5

Cyclic

str

en

gth

, R

l

q -value(MPa)

CPT qc1-value and liquefaction strength

8. RECOMMENDED CHARTS

9. SUMMARY

b-e : Increase in Rl due to N

1 or q

C1 increase

e-d : Increase in Rl due to Kc increase

Liquefaction curve

for Kc>0.5

e

dc

b

(a) Low N1, q

c1

Cyclic

str

en

gth

, R

l

Liquefaction curve

for Kc=0.5

Gradient of liquefaction curve

a

Penetration Resistances N1, q

C1

Schematic Diagram

• For loose deposit:

The gradient due to increase in KC is

much greater than the gradient

coming from the density increase

alone, indicating that the effect of KCon Rl is more significant than the

effect of penetration resistance.

9. SUMMARY

b-e : Increase in Rl due to N

1 or q

C1 increase

e-d : Increase in Rl due to Kc increase

Liquefaction curve for Kc>0.5

e

dc

b

(b) High N1, q

C1

Cyclic

str

en

gth

, R

l

Liquefaction curve

for Kc=0.5

Gradient of liquefaction curve

a

Penetration Resistances N1, q

C1

• For dense deposit:

The gradient of the liquefaction curve

for KC=0.5 is generally high, indicating

that the effect of penetration resistance

is much more significant than the effect

of KC. With increasing KC-value, the

liquefaction strength increases, but its

effect becomes smaller at higher

density.

Schematic Diagram

effect of lateral stress on the liquefaction resistance of scp...

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