Civil Engineering Reference
In-Depth Information
(a)
(b)
Figure 12.22
Rock fall
containment structures: (a) rock
catch ditch with 1.5 m high
gabion along outer edge (Fraser
River Canyon, British Columbia);
(b) barrier constructed with MSE
wall and wire rope fence on top
of wall (Interstate 40 near
Asheville, North Carolina)
(Courtesy: North Carolina
Department of Transportation).
each about 0.6 m thick, built up to form a bar-
rier, which may be as high as 4 m (Threadgold
and McNichol, 1985) (Figure 12.22(b)). By wrap-
ping the fabric around each layer it is possible to
construct a barrier with vertical front and back
faces; the face subject to impact can be protec-
ted from damage with such materials as railway
ties, gabions and rubber tires (Figures 12.23(a)
and (b)). The capacity of a barrier of this type to
stop rock falls depends on its mass in relation to
the impact energy, the shear resistance at the base
and the capacity to deform without failing. The
deformation may be both elastic deformation of
the barrier components, and shear displacement
at the fabric layers or on the base. A disadvantage
of barriers such as those shown in Figure 12.23 is
that a considerable space is required for both the
barrier and the catchment area behind it.
