Environmental Engineering Reference
In-Depth Information
i
Element
in slope
N
i
F
L
= F
R
F
R
Potential
failure
surface
i
W
F
L
T
T
FIGURE 9.63
The infinite slope and forces on an element (total shear
resistance
W
N
U
T
max
N
tan
φ
:
N
W
cos
i
).
and the slope angle
i
for various condi-
tions in a cohesionless material are given in Figure 9.64, in which
T
is the total shearing
resistance, summarized as follows:
Relationships at equilibrium between friction
φ
Dry slope:
i
φ
(angle of repose for sands),
T
N
tan
φ
.
●
Submerged slope:
i
φ
,
T
N
' tan
φ
', and
●
FS
(
W
cos i)tan
φ
'/
W
sin
i
(9.6)
FIGURE 9.64
Equilibrium of an infinite slope in sand under dry, submerged, and slope seepage conditions: (a) slope in dry
sand; (b) submerged slope in sand; (c) seepage in a natural slope; (d) flow net of seepage parallel to slope;
(e) boundary pore pressures; (f) force equilibrium for element with seepage pressures. (After Lambe, T. W. and
