Civil Engineering Reference
In-Depth Information
(a)
3.3 m
Impact transmission bags
Impact catchment bags
MSE-wall
Wall facing
unit
Sandy soil
Geo grid
5.3 m
(b)
Geosynthetic
On-site soil
backfill
Facade of
choice
Concrete
barrier
Slope
Roadway
Rock trap
Figure 12.23
Rock fall barriers constructed with soil and geofabric, and a variety of facings: (a) a 4 m high
Wall with impact energy capacity of 5000 kJ (Protec, 2002); (b) a 2.5 m high wall with energy capacity of
950 kJ (Barrett and White, 1991).
Extensive testing of prototype barriers by the
Colorado Department of Transportation has
shown that limited shear displacement occurs
on the fabric layers, and that they can with-
stand high energy impacts without significant
damage (Barrett and White, 1991). Also, a
4 m high geofabric and soil barriersuccessfully
withstood impact from boulders with volumes
of up to 13 m
3
and impact energies of 5000 kJ
on Niijima Island in Japan (Protec Engineer-
ing, 2002), and a similar 1.8 m wide geofabric
barrier stopped rock impacts delivering 950 kJ of
energy.
