An improved calculation model for predicting the coefficient of restitution and maximum impact force of rockfalls

Abstract

Rockfalls, which are a common natural hazard, collide and continuously bounce along slope surfaces during their movement; the coefficient of restitution (COR) and impact force are two important characteristic parameters related to the impact process of a rockfall. In this paper, considering the elastoplastic characteristics of the ground material, a theoretical model is proposed to obtain the normal COR and normal impact force at different stages of the impact process. Subsequently, the tangential COR and tangential force are calculated based on the improved friction theory. Finally, an engineering case is studied to illustrate the applicability of the proposed model. The calculation results show that the COR is positively correlated with the incident angle under the same incident velocity and negatively correlated with the incident velocity under the same incident angle; the impact force is linearly and positively correlated with the incident velocity. Under a given slope condition, the theory proposed in this paper can explain the locking phenomenon between the boulder and the slope during impact.