Environmental Engineering Reference
In-Depth Information
Table 13.5 Summary of Experimentally Measured Volumetric Deformation Indices
a
One-Dimensional Loading
One-Dimensional Unloading
C
ts
D
ts
G
s
Soil Type
b
Soil Type
b
w
0
G
s
e
0
C
t
or
D
t
G
s
C
m
D
m
G
s
w
0
G
s
e
0
C
ms
D
ms
G
s
DS
0.420
0.699
0.196
0.030
0.124
DS
0.419
0.702
0.040
0.126
0.033
0.263
DS
0.424
0.700
DS
0.421
0.699
OS
0.516
0.606
0.177
0.082
0.158
OS
0.517
0.616
0.055
0.076
0.052
0.101
OS
0.511
0.609
OS
0.514
0.609
DT
0.427
0.642
0.206
0.089
0.159
DT
0.436
0.693
0.066
0.084
0.056
0.122
OT
0.516
0.567
0.179
0.106
0.171
DT
0.523
0.571
0.037
0.057
0.024
0.060
a
All indices have a negative sign, as described by the sign convention.
b
DS stands for silt at dry of optimum initial water content. OS stands for silt at optimum initial water content. DT stands for
glacial till at dry of optimum initial water content. OT stands for glacial till at optimum initial water content.
c
Average slope of unloading curve.
d
Slope of linear portion of unloading curve
contents in Fig. 13.76 can be found using the shrinkage
curve relationship in Fig. 13.77a. The void ratio-matric
suction relationship (i.e., curve 2 in Figs. 13.70 and
13.71) can be constructed using Figs. 13.76 and 13.77.
to an increase in total stress or matric suction can now be
predicted using the computed volume change indices.
The same test procedures were applied to other compacted
silt and glacial till specimens. Figure 13.77b summarizes the
results of shrinkage tests on various compacted specimens.
Typical volume change relationships for the compacted silt
and glacial till are presented in Figs. 13.79, 13.80, and 13.81.
The relationships are similar to that shown in Fig. 13.78. The
computed volume change indices for the compacted silt and
glacial till are tabulated in Table 13.5. These indices can be
converted to other volume change moduli and coefficients.
The slope of the shrinkage curve (i.e.,
de/d
wG
s
or
∂e/∂
u
a
−
u
w
/
∂
wG
s
/∂
u
a
−
u
w
) is equivalent to
the ratio of the volume change indices (i.e.,
C
m
/D
m
G
s
).
The combined plot of Figs. 13.72 and 13.76 and curve 2
(i.e., constructed from Figs. 13.76 and 13.77a) is depicted in
Fig. 13.78, which illustrates the volume change characteris-
tics of an unsaturated, compacted silt. The volume change
indices (i.e.,
C
t
,
C
m
,
D
t
, and
D
m
) can be computed from
Fig. 13.78. Changes in void ratio and water content due
Figure 13.79
Relationship of volume-mass and stress state for silt compacted at optimum water
content (after Ho et al., 1992).
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