ABSTRACT
The downslope mass movement of dry, loose rock material is a common geological process. The mechanics of such phenomena are generally well understood in terms of the interplay between gravity, inertia and inter-granular friction. However, a rare category of dry rock falls or rock slides exists, in which vast horizontal travelling distances are reached with a comparatively small vertical drop in height. These long run-out landslides or, more appropriate, “sturzstroms”, appear to travel as if the coefficient of friction is temporarily reduced by an order of magnitude or more, which usually controls the downslope motion of dry rock debris. Additional universal patterns common to sturzstroms are the increased run-out with increasing failure volume and intensive internal fragmentation. Therefore, a major aim of the present study is to find a joint explanation for features common to all sturzstroms by incorporating, at the particulate level, the new concept of “fluidisation” of rock masses accompanied by fragmentation. This paper focuses on the modelling of such fast moving and fragmenting rock masses by means of 3D particle flow simulations.
