Liquefaction judgment by CPT in consideration of plasticity index. (Part 1)

Yutaka Hojo Jibanshikenjo co. ltd Takeshi Fukasawa JGC Corporation Satoshi Nishihara Chuo Kaihatsu co. ltd Hiroaki Wakatsuki Chiba Engineering co. ltd

Kunio Saito Chuo University Hiroshi Mayuzumi Kawasaki Geological Engineering co. ltd

Jyun Ootsuka Takara Engineering co. ltd

CPT

1.CPT (2001) CPT

(qc) (FL) 24 NCPT N

-1CPT (Ip) (FC)

-1No.

1 2007 No.1 GWL-1.05m 5 6

2 No.1 GWL-1.12m 7.2m No.3 GWL-1.12m 6.4m

3 No.1 GWL-1.72m 5.0m No.2 GWL-1.17m 5.0m

4 No.2 GWL-0.67m 6.0m

2. CPT NCPT N (Ic)

5.022 22.1loglog47.3 rtc FQI ( 1)

vovott qQ ' ( 2)

votsr qfF ( 3) Ic Qt Fr qt (MPa) fs (MPa)

vo (MPa) �vo (MPa)

( 1) Ic -1 Robertson Ic

-1 Qt Fr Ic (D50)

-2 Ic D50

R=-0.77

D50 10mm D101mm

-1,2

CPTIc D50

-1 Qt Fr Ic D50 -2 Ic D50

N (Nc)

MPaqNqIN

tc

Ictcc

2.002.0341.0 0927.034.194.1 ( 4)

Nc N qt (MPa) Ic

( 4) 0.341 Ic1.94 qt/N (qt-0.2)(1.34-0.0927 Ic)

-3 Nc N CPT N 30cmNc/N 1.06 0.69 0.65 0.81

CPT N

3.(FC) 35% (Ip) 15

CPT FC-4 Qt Fr Ic FC Ic FC

FC-5 Ic FC R=0.82 FC 30

70%Ic FC FC

2.4IcFC ( 5)

-6 FC FC CPT

FC/ FC

1.090.810.74

CPTFC

FC35%FC 35%

FC 35%

-5 Ic FC

-4 FC

-3 N Nc

-6 FC FC

4.Ip FC CPT Ip FC

-7 CPT Ip 3 Ip 1520% Ip 10

40% Ip 15

-8 Ip Ip R=0.88

8) ( 6) (Bq) Ip -9 Bq Ip

votq quuB 02 ( 6)

Bq u2 (MPa) u0 (MPa) qt (MPa) vo (MPa)

( 6) Bq Bq

-10 Qt Fr Ip 15

-11 -9 Bq Ip Ip 15 Bq 0.1u2 u0

Ip 15

-12 Robertson Qt Bq Ip=1510) Ip 15

3 4 6Qt Ip 15 Qt 7

Ip 15 Qt 7 Bq 0.1-13 Qt Bq FC=35%

FC 35% Ip 15 Qt 7 Bq 0.1Qt Bq Qt 7 Bq 0.1 FC 35% Ip 15

3 FC 35% Qt7 Bq 0.1

1.Ip=23.4 2.Ip=28.5 3.Ip=29.5

4.Ip=49.2 5.Ip=46.2 6.Ip=37.7

7.Ip=24.3 8.Ip=23.7 9.Ip=9.5

10.Ip=10.4 11.Ip=34.1 12.Ip=8.3

13.Ip=14.4 14.Ip=12.5 15.Ip=8.8

16.Ip=10.8

qt (kPa) fs (kPa) u2 (kPa)

0 10000 1000 20

-18

-17

-16

-15

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

GWL-0.93-1.0-1.5-2.0-2.5-3.0-3.5-4.0-4.5-5.0-5.5-6.0-6.5-7.0-7.5

-12.0-12.5-13.0-13.5-14.0-14.5

-16.0-16.5

1.Ip=23.42.Ip=28.53.Ip=29.54.Ip=49.25.Ip=46.26.Ip=37.77.Ip=24.38.Ip=23.7

9.Ip=9.510.Ip=10.4

11.Ip=34.1

12.Ip=8.313.Ip=14.4

14.Ip=12.515.Ip=8.8

16.Ip=10.8

32

46

22 20

47

3313

49

38

1

4554

2

42

56

4

52

44

12

59

299

57

35 37

48

16

37

44

19 7

51

42 42

41

18

25

53

22 28

53

1942

42

16

44

37

19

-7 CPT 3

-9

-10 Ip (Qt Fr)

-12 Ip (Qt Bq)

(Qt-Bq) 1. 2. 3. 4.5. 6. 7.

-11 Bq Ip

-13 FC (Qt Bq)

-8 Ip

5.N Nc N -3 Nc/N 1.06

0.69 0.65 0.81 CPT N

FC FC -6 FC/ FC1.09 0.81 0.74 0.82 CPT FC

FC 35%-7 3 CPT Ip 15 20%

Ip 10 40%-8 Ip Ip R=0.88-12 Robertson Qt Bq Ip Ip 15 3

4 6 Qt 7 Bq 0.1-13 Robertson Qt Bq FC FC 35 Ip Qt 7Bq 0.1

Qt 7 Bq 0.1 FC 35% Ip 15 FC FC35% Robertson Qt Bq Qt 7 Bq 0.1

6.Ip FC Key Qt Bq

Ip

1) pp.132 149 20122) SPT CPT GeoKanto2013 4-1 20133) 2007 Vol.57 No.8 20094) 47

pp.131 132 20125) 48

pp.343 345 20136) Robertson, P.K. and Wride, C.E. Evaluating Cyclic Liquefaction Potential using the CPT, Canadian Geotechnical Journal, Vol. 35,

No. 3. 1998. 7)

566 73-80 20038) 27 163-166 19929) Robertson,P.K. Soil classification using the cone penetration test. Canadian Geotechnical Journal,27(1),151-8. 1990. 10) No,799 -72 153-170 2005