Civil Engineering Reference
In-Depth Information
6.18
Before Improvement
Cyclic stress ratio
N
value corrections
CRR
v
,
Depth,
m
v
,
(see
FS
kPa
kPa
v
/
v
r
d
CSR
N
value
C
r
N
60
C
N
(
N
1
)
60
Notes)
CRR/CSR
0.5
9.45
9.45
1.00
0.99
0.26
16
0.75
12
3.24*
39
0.5
2
1.5
29.1
19.3
1.51
0.98
0.38
11
0.75
8.3
2.28*
19
0.25
0.66
2.5
48.7
29.1
1.67
0.97
0.42
9
0.75
6.8
1.85
13
0.18
0.43
3.5
68.3
38.9
1.76
0.96
0.44
12
0.75
9.0
1.60
14
0.19
0.42
4.5
87.9
48.7
1.80
0.95
0.44
19
0.85
16
1.43
23
0.33
0.76
5.5
108
58.5
1.85
0.93
0.45
11
0.85
9.4
1.31
12
0.16
0.36
6.5
127
68.3
1.86
0.92
0.44
9
0.95
8.6
1.21
10
0.14
0.32
7.5
147
78.1
1.88
0.91
0.44
19
0.95
18
1.13
20
0.26
0.59
8.5
166
87.9
1.89
0.90
0.44
10
0.95
9.5
1.07
10
0.14
0.32
9.5
186
97.7
1.90
0.89
0.44
10
0.95
9.5
1.01
10
0.14
0.32
10.5
206
107
1.93
0.88
0.44
11
1.00
11
0.97
11
0.15
0.34
11.5
225
117
1.93
0.86
0.43
4
1.00
4.0
0.92
3.7
0.07
0.16
12.5
245
127
1.93
0.85
0.43
10
1.00
10
0.89
8.9
0.13
0.30
13.5
264
137
1.93
0.84
0.42
11
1.00
11
0.85
9.4
0.13
0.31
14.5
284
147
1.93
0.83
0.42
12
1.00
12
0.82
10
0.14
0.33
15.5
304
156
1.95
0.81
0.41
13
1.00
13
0.80
10
0.14
0.34
Notes:
Cyclic stress ratio:
a
max
0.40
g, r
d
from Eq. (6.7).
N
value corrections:
E
m
0.6,
C
b
1.0,
C
N
from Eq. (5.2). CRR from Fig. 6.6 (silty sand
with 15 percent fines). The values of CRR from Fig. 6.6 were multiplied by a magnitude scaling factor
0.89 (see Table 6.2).
*Suggested maximum values of
C
N
range from 1.7 to 2.0 (Youd and Idriss 1997, 2001).
