Environmental Engineering Reference
In-Depth Information
Tension cracks
N
MA
T
B
L
1
C
D
F
Residual strength
r
J
L
2
X
G
FIGURE 9.74
Geometry of two intersecting joint sets failing
progressively (the multilinear failure surface). (From
Barton, N.,
Proceedings of ASCE, 13th Symposium on
Rock Mechanics,
Urbana, Illinois [1971], 1972, pp.
139-170. With permission.)
Peak strength
D
Line of
intersection
Slope face
Wedge
FIGURE 9.75
Geometry of a triangular wedge.
Contours of equal values
of safety factor
Minimum
safety
factor
o
R
Moment arm of
W
is
E
W
(a)
E
L
Disturbed
shear
stresses (d)
Pore pressure (b)
Disturbed normal
effective stresses (c)
(a)
r
r
c
r
W
R
c
U
R
N
FIGURE 9.76
Forces acting on a free body with circular failure: (a)
distributed stresses and (b) resultant forces.
(b)
