Environmental Engineering Reference
In-Depth Information
TABLE 3.14
Typical Permeability Coefficients for Various Materials
a
Particle-Size Range
“Effective” Size
Permeability Coefficient
k
Inches
Millimeters
D
max
D
min
D
max
D
min
D
14
, in
D
15
, (mm)
ft/year
ft/month
cm/sec
Turbulent Flow
Derrick atone
120
36
48
100
10
6
100
10
5
100
One-man stone
12
4
6
30
10
6
30
15
5
30
Clean, fine to coarse gravel
3
¼
80
10
½
10
10
6
10
10
5
10
Fine, uniform gravel
3/8
1/16
8
1.8
1/2
5
10
6
5
10
5
5
Very coarse, clean, uniform tend
1/8
1/32
3
0.8
1/16
3
10
6
3
10
5
3
Laminar Flow
Uniform, coarse sand
1/8
1/64
2
0.5
0.6
0.4
10
6
0.4
×
10
5
0.4
Uniform, medium sand
0.5
0.25
0.3
0.1
10
5
0.1
10
5
0.1
Clean, well-graded sand and gravel
10
0.05
0.1
0.01
10
5
0.01
10
5
0.01
Uniform, fine sand
0.25
0.05
0.06
4000
400
40
10
−4
Well-graded, silty sand and gravel
5
0.01
0.02
400
40
4
10
−4
Silty sand
2
0.005
0.01
100
10
10
−
4
Uniform silt
0.05
0.005
0.006
50
5
0.5
10
−4
Sandy clay
1.0
0.001
0.002
5
0.5
0.05
10
−4
Silty clay
0.05
0.001
0.0015
1
0.1
0.01
10
−4
Clay (30-50% clay sizes)
0.05
0.0005
0.0008
0.1
0.01
0.001
10
−4
Colloidal clay (
−
2
µ
m
≤
50%)
0.01
10Å
40Å
0.001
10
4
10
9
a
From Hough, K.B.,
Basic Soils Engineering,
The Ronald Press, New York, 1957.
