Investigating the influence of collision property and fragmentation on rock fall with 3D ETM modelling.

The natural hazard of rockfall might be caused by earthquake, freeze/thaw action, rainfall, weathering and the erosion of rocks. Due to the limitation by site conditions, field tests cannot be conducted adequately. To acquire a better knowledge of the rockfall mechanism, the three-dimensional (3D) energy tracking method (ETM) is used to investigate the influence of collision property and fragmentation on the trajectories of rock blocks. According to the numerical results, when the rock blocks collide with the gentle slope, their velocities and total kinetic energy decrease sharply. The fragmentation phenomenon mainly occurs at the gentle slope, which leads to the obvious decreasing of velocity and total kinetic energy. When the collision restitution of rock blocks increases, more rock blocks are able to pass through the gentle slope. When the friction coefficient increases or the fragmentation phenomenon occurs, more rock blocks stop at the gentle slope. Additionally, the increasing of collision restitution and fragmentation phenomenon leads to the increasing of invasion zone width. The present 3D ETM–based simulator is potentially useful to optimize the design of protection measures and control geo-hazard. [ABSTRACT FROM AUTHOR]