Civil Engineering Reference
In-Depth Information
Table 14.1
Equilibrium suction-index CBR values. Reproduced from TRRL Report LR1132 (1984).
Plasticity
index
Type of soil
High water table
Low water table
Construction conditions:
Construction conditions:
Poor
Average
Good
Poor
Average
Good
Thin
Thick
Thin
Thick
Thin
Thick
Thin
Thick
Thin
Thick
Thin
Thick
Heavy clay
70
1.5
2
2
2
2
2
1.5
2
2
2
2
2.5
60
1.5
2
2
2
2
2.5
1.5
2
2
2
2
2.5
50
1.5
2
2
2.5
2
2.5
2
2
2
2.5
2
2.5
40
2
2.5
2.5
3
2.5
3
2.5
2.5
3
3
3
3.5
Silty clay
30
2.5
3.5
3
4
3.5
5
3
3.5
4
4
4
6
Sandy clay
20
2.5
4
4
5
4.5
7
3
4
5
6
6
8
10
1.5
3.5
3
6
3.5
7
2.5
4
4.5
7
6
>
8
Silt
*
1
1
1
1
2
2
1
1
2
2
2
2
−
Sand
−
20
(poorly graded)
Sand
40
−
(well graded)
Sandy gravel
60
−
(well graded)
* estimated assuming some probability of material saturating.
