Experimental and DEM analysis of the dissipation involved in the collision of a boulder with a substratum

Experiments and numerical analysis were both carried out to evaluate the amount of energy dissipated during the rebound between single boulder (concrete made blocks with many varied shapes) and a soft or stiff substratum. A high speed camera made it possible to analyze the collision kinematics and to determine the role played by different features such as the incident axial/angular velocities, the boulder shapes, the impact configuration and the substratum type, on the amount of dissipated energy. A three-dimensional discrete element code was used to simulate the experiments by accounting for the actual shape of the boulder and some dissipation mechanisms. The comparison between the experimental and numerical trajectories allowed for an physical interpretation of the dissipation mechanisms and an identification of a set of parameters to be introduced in the simulations. That way, the predictive ability of the discrete model of rock avalanche can be improved by including in-situ measurements.