Civil Engineering Reference
In-Depth Information
7.7
Use the data from the example problem in Sec. 7.2.2, but assume that the soil type
is gravelly sand (i.e., soil type 3, see Fig. 6.12) and at a depth of 3 m,
q
c
1
14 MPa.
Calculate the settlement, using Figs. 7.1 and 7.2.
Answer:
See Table 7.3.
7.8
Use the data from the example problem in Sec. 7.2.2, but assume that the soil type
is eolian sand (i.e., soil type 4, see Fig. 6.12). Calculate the liquefaction-induced settlement,
using Figs. 7.1 and 7.2.
Answer:
See Table 7.3.
7.9
Use the data from the example problem in Sec. 7.2.2, but assume that the soil type
is noncemented loess (i.e., soil type 7, see Fig. 6.12). Calculate the liquefaction-induced
settlement, using Figs. 7.1 and 7.2.
Answer:
See Table 7.3.
7.10
Assume a site has clean sand and a groundwater table near ground surface. The
following data are determined for the site:
Layer depth, m
Cyclic stress ratio
(
N
1
)
60
2-3
0.18
10
3-5
0.20
5
5-7
0.22
7
Using Figs. 7.1 and 7.2, calculate the total liquefaction-induced settlement of these layers
caused by a magnitude 7.5 earthquake.
Answer:
Per Fig. 7.1, 22 cm; per Fig. 7.2, 17 cm.
Liquefaction-Induced Settlement, Subsoil Profiles
7.11
Use the data from Prob. 6.12 and the subsoil profile shown in Fig. 6.13. Ignore any
possible settlement of the soil above the groundwater table (i.e., ignore settlement from ground
surface to a depth of 1.5 m). Also ignore any possible settlement of the soil located below a
depth of 21 m. Using Figs. 7.1 and 7.2, calculate the earthquake-induced settlement of the sand
located below the groundwater table.
Answer:
Per Fig. 7.1, 61 cm; per Fig. 7.2, 53 cm.
7.12
Use the data from Prob. 6.15 and the subsoil profile shown in Fig. 6.15. Ignore
any possible settlement of the surface soil (i.e., ignore settlement from ground surface to a
depth of 1.2 m). Also ignore any possible settlement of soil located below a depth of 20 m.
Using Figs. 7.1 and 7.2, calculate the earthquake-induced settlement of the sand located
below the groundwater table.
Answer:
Per Fig. 7.1, 22 cm; per Fig. 7.2, 17 cm.
7.13
Figure 7.12 shows the subsoil profile at the Agano River site in Niigata. Assume
a level-ground site with the groundwater table at a depth of 0.85 m below ground surface.
The medium sand, medium to coarse sand, and coarse sand layers have less than 5 percent
fines. The fine to medium sand layers have an average of 15 percent fines. The total unit
weight
t
of the soil above the groundwater table is 18.5 kN/m
3
, and the buoyant unit weight
b
of the soil below the groundwater table is 9.8 kN/m
3
.
The standard penetration data shown in Fig. 7.12 are uncorrected
N
values. Assume a
hammer efficiency
E
m
of 0.6 and a boring diameter of 100 mm; and the length of drill rods
is equal to the depth of the SPT below ground surface. The design earthquake conditions
are a peak ground acceleration
a
max
of 0.20
g
and magnitude of 7.5. Based on the standard
penetration test data and using Figs. 7.1 and 7.2, calculate the earthquake-induced settle-
ment of the soil located at a depth of 0.85 to 15.5 m below ground surface.
Answer:
Per
Fig. 7.1, 30 cm; per Fig. 7.2, 24 cm.
7.14
Figure 7.13 shows the subsoil profile at a road site in Niigata. Assume a level-
ground site with the groundwater table at a depth of 2.5 m below ground surface. Also
assume that all the soil types located below the groundwater table meet the criteria for
potentially liquefiable soil. The medium sand layers have less than 5 percent fines, the
