Numerical modelling of the flexural deformation of foliated rock slopes

Toppling failure of slopes in a foliated (layered) rock mass occurs essentially due to tensile breaking of rock columns where there are no cross-joints to act as the basal planes of blocks. The rock columns under their self-weight freely bend into the excavation and induce tensile (bending) stresses. Thus, the knowledge of deflection (bending) of the rock columns and resulting stresses plays a major role in the stability analysis of such slopes. A continuum model based on the Cosserat theory, which includes the bending (couple) stresses in its formulation, has been devised and incorporated into a finite element code. The numerical results have been compared with the results of centrifuge experiments and the comparison shows agreement suggesting that the model is capable of reproducing a complex pattern of load-displacement behaviour as seen in the centrifuge models. The Cosserat model has proven to be a useful tool for predicting the behaviour of slopes in a foliated rock mass. The Cosserat model has also been used to verify the existence of a limiting equilibrium state in foliated rock slopes as assumed in the Aydan and Kawamoto model. Copyright (C) 1996 Elsevier Science Ltd