Evaluation of Global Safety Factor of Slopes during Rainfall

Abstract

The rise of ground water level caused by rainfall is one of the main reasons for which landslides and slope failures take place. In this paper numerical analysis of water flow through unsaturated-saturated soils is performed based on the finite element program in Fortran 90. The rainfall effect on the stability of slopes is predicted by the elasto-plastic shear strength reduction finite element method, in which the water pressure head is obtained from the previous analysis of transient water flow through unsaturated-saturated soils. The calclated results indicate that the patterns and values of the rise of ground water level in slopes due to infiltration of the rainfall are greatly influenced by the hydraulic properties of soils. It is shown that the present method is suit able for evaluating the rainfall effect on the stability of slopes in practice.