Civil Engineering Reference
In-Depth Information
UDEC (Version 3.20)
500
Legend
400
Cycle 750880
Time 1.083E + 03 sec
Y displacement contours
Contour interval = 2.0
300
(zero contour line omitted)
200
-12
-8
-
-4
-2
0
-10
100
Block plot
0
-100
Horizontal axis (m)
0
100
200
300
400
500
600
700
Figure 10.12
Flexural toppling failure mode determined with UDEC.
(a)
(b)
Figure 10.13
A schematic
representation of slopes in a foliated
rock mass: (a) flexural toppling; and
(b) flexural buckling (Adhikary
et al.
,
2001).
in the computational model by calculating, for
each zone, the forces generated by deformation of
an “active length” of the element where it crosses
a discontinuity (see Figure 6.9). This formula-
tion exploits simple force-displacement relations
to describe both the shear and axial behaviors of
reinforcement across discontinuities. Large shear
displacements are accommodated by consider-
ing the simple geometric changes that develop
locally in the reinforcement near a discontinu-
ity. Although the local reinforcement model can
be used with either rigid blocks or deformable
blocks, the representation is most applicable to
cases in which deformation of individual rock
blocks may be neglected in comparison with
deformation of the reinforcing system. In such
cases, attention may be focused reasonably on
the effect of reinforcement near discontinuities.
The original description of a local reinforcement
model is given by Lorig (1985).
In assessing the support provided by rock
reinforcement, two components of restraint
should be considered. First, the reinforce-
ment provides local restraint where it crosses
