Numerical Simulation of Effects of Slope Micro-Topography on Rockfall Trajectories

Abstract

Rockfall hazard zoning is not simple to achieve in practice. It involves the different factors: rock block shape and size, characteristics of the topography, and the occurrence of rockfall which depends on some triggering events that cause a change in the forces acting a rock block. Rockfall hazard maps are often replaced with figures which show the frequency and the corresponding intensity of a predefined rock magnitude. Some attempts are introducing the results of the three-dimensional numerical modeling to get the objective zoning based on the mechanical parameters (e.g. kinetic energy). In such attempts, it is important to recognize that the mechanical parameters may be affected by modeling of the physical factors mentioned above. The most important role of the three-dimensional simulation is to display the lateral dispersion of trajectories. In this paper, the influence of controlling factors on the dispersion has been evaluated by conducting 3D simulation. Parametric simulations have been performed at different spatial resolutions using sets of synthetic biplanar slopes characterized by mean inclination and local asperities. The results of the lateral dispersion of trajectories are explained with the width of computed trajectories and the fixed distance along the slope surface from the block launch position.