Geoscience Reference
In-Depth Information
Table 8.3
Permeability based on Hazen's relationship.
Coarse grained size
Fine sands
Medium sands
Coarse sands
>
>
>
Effective grain size d
10
,mm
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Cd
10
)
10
−
4
m/s
10
−
3
m/s
10
−
2
m/s
Permeability (k
=
C
0.10 (above equation)
1
4
0.9
1.6
2.5
3.6
4.9
6.4
0.8
1.0
=
C
0.15
1.5
6
1.4
2.4
3.8
5.4
7.4
9.6
1,2
1.5
=
Table 8.4
Permeability based on soils classification.
Soil type
Description
USC symbol
Permeability, m/s
Well graded
GW
10
−
3
to 10
−
1
Poorly graded
GP
10
−
2
to 10
Gravels
Silty
GM
10
−
7
to 10
−
5
10
−
8
to 10
−
6
Clayey
GC
10
−
5
to 10
−
3
Well graded
SW
10
−
4
to 10
−
2
Poorly graded
SP
Sands
10
−
7
to 10
−
5
Silty
SM
Clayey
SC
10
−
8
to 10
−
6
Low plasticity
ML
10
−
9
to 10
−
7
Inorganic silts
High plasticity
MH
10
−
9
to 10
−
7
Low plasticity
CL
10
−
9
to 10
−
7
Inorganic clays
High plasticity
CH
10
−
10
to 10
−
8
Organic
with silts/clays of low plasticity
OL
10
−
8
to 10
−
6
with silts/clays of high plasticity
OH
10
−
7
to 10
−
5
Peat
Highly organic soils
Pt
10
−
6
to 10
−
4
•
Does not account for structure or stratification.
8.5 Permeability from dissipation tests
•
The measurement of in situ permeability by dissipation tests is more reliable than
the laboratory testing, due to the scale effects.
•
The laboratory testing does not account for minor sand lenses, which can have
significant effect on permeability.
Table 8.5
Coefficient of permeability from measured time to 50% dissipation (Parez and Fauriel, 1988).
Hydraulic
10
−
3
to 10
−
5
10
−
4
to 10
−
6
10
−
6
to 10
−
7
10
−
7
to 10
−
9
10
−
8
to 10
−
10
conductivity, k (m/s)
Sand and
Silty sand to
Soil Type
Sand
Silt
Clay
gravel
sandy silt
t
50
(sec)
0.1 to 1
0.3 to 10
5 to 70
30 to 7000
5000
>
t
50
(min/hrs)
<
0.2 min
0.1 to 1.2 min
0.5 min to 2 hrs
>
1.5 hrs
Search WWH ::
Custom Search