Environmental Engineering Reference
In-Depth Information
Silt
Sand
Gravel
100
80
Boundaries
for most
liquefiable soil
60
40
Boundaries
for potentially
liquefiable soil
20
0
0.01
0.1
1.0
10
Grain size (mm)
Figure 12.15.
Limits in the particle size gradation curves separating liquefiable and unliquefiable soils
as suggested in 1985 by USNRC (USNRC, 1985).
100
Ranges of grain size
for tailings slimes
with low resistance
to liquefaction
80
60
Boundary for
potentially
liquefiable soil
40
Boundary for most
liquefiable soil
20
0
0.1
0.01
0.001
Grain size (mm)
Figure 12.16.
Ranges of particle size gradation curves for mine tailings with low resistance to liquefac-
tion as suggested in 1985 by USNRC (Ishihara, 1985; USNRC, 1985).
suggested range of soils susceptible to flow liquefaction. This data would be more reliable
than Figure 12.5.
Seed and Idriss (1982), based on data on liquefaction in China produced by Wang
(1979, 1981), recognised that clayey soils could liquefy provided their water content was
high (relative to the liquid limit), the soils were not too plastic and not too much clay was
present. They proposed that liquefaction can occur only if all three of the following crite-
ria are met:
- The “clay” content (particles smaller than 0.005 mm) is
15% by weight;
- The liquid limit is
35%;
- The natural moisture content is
0.9 times the liquid limit.
