A rheological model for the description of boulder impacts on granular strata

Abstract

This paper considers the mechanics of rock boulders impacting on granular strata. The study is aimed at improving the numerical methods devoted both to describing boulder trajectories along slopes and designing preventive structures in mountain regions. The problem is analysed by using a simplified approach inspired by the lumped mass method. This is based on (a) the macro-element concept, (b) the definition of generalised stresses and displacements, and (c) delayed plasticity theory. Both vertical and inclined impacts on horizontal strata and vertical impacts on inclined slopes are discussed. The numerical results are obtained by using a finite difference numerical discretisation to integrate, over time, a coupled system of two-dimensional differential equations. Most of the input data requested by the model are basic and geotechnically meaningful, and comparison of the numerical results with the experimental data seems to be quite promising.