MECHANISMS OF FAILURE AND SLOPE DEVELOPMENT IN ROCK MASSES

This paper examines the mechanisms of failure in jointed rock slopes. The distribution of discontinuities is a significant control of rock-m ass stability, determining the mechanism by which blocks fail from a c liff and the consequent slope development through time. It is often as sumed that the principles of single-block movements are geomechanicall y similar to those of larger, multiple-block rock-mass failures, under a given set of boundary conditions and controlling variables. Results presented here, based on computer modelling using the Universal Disti nct Element Code (UDEC), show that such assumptions are not always cor rect. After a theoretical modelling exercise, real-world rock slopes w ere studied from the Portland Limestone outcrop of the Isle of Purbeck , England. There is good association between the theoretical results a nd model output for the fieldsites. The conclusions are thus useful in enhancing knowledge of jointed rock-mass failure conditions, and impr oving understanding of rock-slope development.