Geology Reference
In-Depth Information
1.30
e
o
= 1.249
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.75
100
1,000
10,000
100,000
Pressure, p (lb/ft
2
)
Figure 20-5
Void Ratio versus Logarithm of Pressure
The coefficient of consolidation can now be computed by substituting
into Eq. (20-8):
(0.196)(0.385)
2
8.2
c
v
3.54
10
3
in.
2
min
>
The values computed are listed in the second row (corresponding to
500 lb/ft
2
) of the data form on page 311. Each additional loading on the
test specimen will furnish a set of time-versus-deformation dial read-
ings, which through subsequent evaluation will provide a coefficient of
consolidation,
c
v
, corresponding to a specific loading, or pressure,
p
. Such
additional loadings (and subsequent analyses) would be listed in the
remaining rows of the data form. Although no laboratory data are given
herein for additional loadings on the test specimen, succeeding rows
for loadings of
1,000, 2,000, 4,000, 8,000,
and
16,000 lb/ft
2
have been
included on the form on page 311 in order to demonstrate the complete
evaluation of a consolidation test.
A graph of pressure (the first column on page 311) along the ab-
scissa on a logarithmic scale versus coefficient of consolidation (the last
column on page 311) along the ordinate on an arithmetic scale can
be prepared. This graph, which is known as the
c
v
- log
p
curve (i.e.,
coefficient of consolidation versus the logarithm of pressure), is one of
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