TM 5-818-1 / AFM 88-3, Chap. 7
f.
Coefficient of consolidation.
where
The soil
k=
coefficient of permeability in a vertical
properties that control the drainage rate of pore water
direction
=
initial void ratio
e0
defined as follows:
=
unit weight of water
yy
∆e/∆p = coefficient of compressibility,
k(1 + e0) = k
(3-10)
Cv =
=
av
ywav'
ywmv
vertical deformation
mv =
coefficient of volume compressibility
alternatively,
T
=
Time factor (para 5-5) that depends on
2
TH
(3-11)
Cv =
percent consolidation and assumed
t
pore pres-
Table 3-3. Compression Index Correlations
Clays
Cc = 0.012 w , wn in percent
Cc = 0.01 (LL-13)
Sand, uniform
Cc = 0.03 , loose to Cc = 0.06, dense
Silt, uniform
Cc = 0.20
U. S. Army Corps of Engineers
Table 3-4. Value of Coefficient of Compressibility (mv) for Several Granular Soils During Virgin Loading
10-4
mv x
per psi
Relative
Effective Pressure
9 to 14 psi
28 to 74 psi
Soil
Density, DR
Uniform gravel
0
2.3
1.1
1 < D < 5 mm
100
0.6
0.4
Well-graded sand
0
5.0
2.7
0.02 < D < 1 mm
100
1.3
0.6
Uniform fine sand
0
4.8
2.0
0.07 < D < 0.3 mm
100
1.4
0.6
Uniform silt
0
25.0
4.0
0.02 < D < 0.07 mm
100
2.0
0.9
(Courtesy of T W. Lambe and R. V. Whitman, Soils
Mechanics, 1969, p 155. Reprinted by permission of
John Wiley & Sons, Inc., New York.)
3-12
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