Comparison study between traditional and finite element methods for slopes under heavy rainfall

Abstract

In this paper, a comparison study has been carried out between the limit equilibrium (conventional) methods and finite element method of estimation factor of safety of slopes under the effect of rainfall. A case study is analyzed with the finite element method, and the results are compared with outcomes from some of the well-known conventional methods namely: simplified Bishop Method (1955), simplified Janbu method (1954), and Fellenius method (1927).Moreover, slope stability concerning rainfall and infiltration is analyzed. Specially, two kinds of infiltrations (saturated and unsaturated) are considered. Many slopes become saturated during periods of intense rainfall or snowmelt, with the water table rising to the ground surface, and water flowing essentially parallel to the direction of the “slope” and “Influence” of the change in shear strength, density, pore-water pressure and seepage force in soil slices on the slope stability is explained. Finally, it is found that classical limit equilibrium methods are highly conservative compared to the finite element approach. For assessment the factor of safety for slope using the later technique, no assumption needs to be made in advance about the shape or location of the failure surface, slice side forces and their directions. This document outlines the capabilities of the finite element method in the analysis of slope stability problems.