Geoscience Reference
In-Depth Information
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Computing the rock fall motion and remedial measures allows greater flexibilities,
in terms of rock sizes, probabilities, varying slope changes, benching, etc. The
coefficient of restitution is required in such analysis.
14.26 Coefficient of restitution
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There are some inconsistencies in various quoted values in referenced paper from
various sources.
Table 14.26
Coefficient of restitution (Richards, 1991).
Type of material on slope surface
Coefficient of restitution
r
Normal r
n
Tangential r
t
Impact between competent materials (Rock-rock)
0.75-0.80
Impact between competent rock and soil scree
0.20-0.35
material
Solid rock
0.9-0.8
0.75-0.65
Detrital material mixed with large rock boulders
0.8-0.5
0.65-0.45
Compact detrital material mixed with small boulders
0.5-0.4
0.45-0.35
Grass covered slopes or meadows
0.4-0.2
0.3-0.2
14.27 Rock cut stabilization measures
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Rock slopes that are considered unstable need stabilization or protective measures
needs to be considered.
Table 14.27
Rock slope stabilization considerations.
Consideration
Solution
Methods
Comment
Eliminate
Rock Removal
Relocate structure/service/road/rail
Relocation is often not
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Problem
Resloping
possible. Resloping
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Trimming and scaling
requires additional land
Stabilization
Reinforcement
Drainage
Often expensive
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Berms
solutions
Rock Bolting and Dowels
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Tied Back walls
Shotcrete facings
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Reduce Hazard
Protection
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Mesh over slope
Controls the rock falls.
Measures
Rock Trap ditches
Usually cheapest
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Fences
solution. Requires some
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Berms
maintenance e.g. clearing
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Barriers and impact walls
rock behind mesh
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False Tunnels
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