Improvement of fine-grained and cohesive soils 163
factor β 1  according to Priebe (1995) can be calculated using, for example,
Equation 4.52:
β 1 2 3
= .
(4.77)
The assessment of the bearing capacity now follows the procedure as
proposed by Barksdale and Bachus (1983) and as described in Section
4.3.3 using characteristic parameters and first calculating a characteristic
bearing resistance R k . Using partial safety factors for actions and resistances it then needs to be shown (according to Eurocode 7) that
V d ≤ R d
(4.78)
10.1 MN
−13.0 m
5.8 m
+ + + + +
+ + + + +
+ + + + +
+ + + + +
+ + + + +
1.4 m
0.7 m
5.8 m
–1.9 m
0.0 m
1.4 m
1.4 m
1.4 m
1
2
Figure 4.31 Cross section and plan view of single footing founded on 25 stone columns.
Table 4.9 Characteristic soil parameters
Layer 1: fill
Layer 2: marl
Stone columns
Unit weight γ (kN/m 3 )
16
22
21
Submerged unit weight γ′ (kN/m 3 )
6
10
11
Constrained modulus E oed (MN/m 2 )
–
20
120
Poisson’s ratio µ
–
0.45
0.33
Young’s modulus E (MN/m 2 )
–
5.3
81
Effective friction angle φ′ (°)
–
27
40
Effective cohesion c′ (kN/m 2 )
–
10
0
Undrained shear strength c u (kN/m 2 )
–
25
–
Coefficient of earth pressure at rest K 0
–
0.55
–