Environmental Engineering Reference
In-Depth Information
V
W
sin i
W
cos
i
W
C
U
FIGURE 9.66
Block with cleft water pressures
and cohesion.
i
(
W
cos
i
−
U
) tan
W
cos
W
W
sin
cL
(
W
cos
)
−
U
U
(
W
cos
−
U
) tan
FIGURE 9.67
Simple wedge acting along continuous surface
with cohesion.
slope
(
Figure 9.68b)
.
Figure 9.69
gives an example of a simple wedge developing in resid-
ual soils. In Figure 9.68,
FS
[
cL
(
W
cos
θ
U
V
sin
θ
) tan
φ
]/
W
sin
θ
V
cos
θ
(9.10)
where
L
(
H
z
) cosec
θ
,
U
1/2
γ
w
z
w
(
H
z
) cosec
θ
,
V
1/2
γ
w
z
w
2
,
W
1/2
γ
t
H
2
{[1
(
z
/
H
)
2
]cot
θ
cot
i
}
(Figure 9.68a)
or
W
1/2
γ
t
H
2
{[1
z
/
H
)
2
cot
θ
(cot
θ
tan
i
1)]
(Figure 9.68b)
Case 5
: Single planar failure surface in clay: location unknown; Culmann's simple wedge
(
Figure 9.70)
.
Assumptions are that the failure surface is planar and passes through the