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-mass stability, determining the mechanism by which blocks fail from a cliff, and the consequent slope development through time. It is often assumed that the principles of single-block movements are geomechanically 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 Distinct Element Code (UDEC), show that such assumptions are not always correct. After a theoretical modelling exercise, real-world rock slopes were studied from the Portland Limestone outcrop of the Isle of Purbeck, England. There is good association between the theoretical results and model output for the fieldsites. The conclusions are thus useful in enhancing knowledge of jointed rock-mass failure conditions, and improving understanding of rock-slope development.