Trajectory Analysis and Risk Evaluation of Dangerous Rock Mass Instability of an Overhang Slope, Southwest of China

Table 5

Range of restitution coefficient (according to Chen et al. [27]).

Slope characteristics	Rn (normal recovery coefficient)	Rt (tangential recovery coefficient)
Smooth hard rock surface, paved concrete surface	0.25∼0.75	0.88∼0.98
Soft rock face, strong weathered hard rock face	0.15∼0.37	0.78∼0.95
Rock pile slope	0.15∼0.37	0.75∼0.95
Rubble dense, hard surface slope, the vegetation growth, to shrub	0.12∼0.33	0.30∼0.95
Dense gravel pile, hard soil slope, no or little vegetation development	0.12∼0.32	0.65∼0.95
Loose gravel piles, soft soil slopes, well-developed vegetation, mainly shrubs	0.10∼0.25	0.30∼0.80
Soft soil slope, no or little vegetation development	0.10∼0.30	0.50∼0.80