Civil Engineering Reference
In-Depth Information
Assume that the Japanese
N
1
value is approximately equal to the (
N
1
)
60
value. Using the
above factors of safety against liquefaction and the given (
N
1
)
60
value gives
For the 2- to 3-m layer:
v
3.5% or settlement
0.035 (1.0)
0.035 m
For the 3- to 5-m layer:
v
4.8% or settlement
0.048 (2.0)
0.096 m
For the 5- to 7-m layer:
v
4.3% or settlement
0.043 (2.0)
0.086 m
Total settlement
0.035
0.096
0.086
0.22 m
22 cm
Solution using Fig. 7.2:
Enter the curve with the given (
N
1
)
60
and CSR values:
For the 2- to 3-m layer:
v
2.6% or settlement
0.026 (1.0)
0.026 m
For the 3- to 5-m layer:
v
4.2% or settlement
0.042 (2.0)
0.084 m
For the 5- to 7-m layer:
v
3.2% or settlement
0.032 (2.0)
0.064 m
Total settlement
0.026
0.084
0.064
0.174 m
17 cm
7.11
See page E.16.
7.12
See page E.17.
7.13
See pages E.18 and E.19.
7.14
See pages E.20 and E.21.
7.15
See pages E.22 and E.23.
7.16
Assume that with soil improvement there will be no settlement in the upper 15 m
of the soil deposit. The only remaining liquefiable soil layer is at a depth of 17 to 20 m. The
stress increase due to the building load of 50 kPa at a depth of 17 m can be estimated from
the 2:1 approximation, or
qBL
_____________
v
(
B
z
) (
L
z
)
where
z
depth from bottom of footing to top of liquefied soil layer
17
1
16 m
L
20 m
B
10 m
q
50 kPa
