Three problems in slope stability analyses with finite element method

To study the slope stability with shear strength reduction technique, a large finite element (FE) software, ABAQUS, is customized and linked into our program with the function of automatic searching for the safety factor. Based on results from FE model developed, three indicators of slope failure, e.g. non-convergence of solution, the plastic zone extending from the slope toe to the top and the critical value of plastic strain along the potential failure surface, are discussed. Furthermore, the inherent association of three failure indicators is illustrated. The non-convergence criterion is fit for coding the program with automatic searching for safety factor, as well as less dependant on users' experiences. In most cases the order of mesh elements slightly affects the safety factor, but linear elements tend to overestimate the safety factor sometimes. It is thus advised to adopt second-order elements. Large deformation FE analyses for slope stability were carried out in updated Lagrangian formulation; and it is found the non-convergence criterion can not be taken as a reasonable indicator of slope failure.