Slope stability analysis using finite element method

Abstract

Traditionally, geotechnical engineers often use limit equilibrium method to find out the factor of safety for slope stability problems. As the technology advance, finite element analysis has become popular among geotechnical engineers. It is applicable for many complex conditions that are not possible with the limit equilibrium method.

This project explores the use of the finite element method to determine the factor of safety and also to examine how factor of safety varies in different case studies with different soil profile as well as the pile effect and the pile location.

The PLAXIS finite element software was used to carry out analysis of slope stability in soil. There are 5 cases for the homogenous slopes and 3 cases for the multi-layered soils to be compared. For the simple homogenous slopes, it is found that the results from limit equilibrium method and finite element method are generally in good agreement for = 45°. As for the multi- layered soils, the factor of safety is more stable when there is a constant friction angle with variations in the cohesion.

Flexible steel pile produces higher factor of safety as compared to concrete pile and the factor of safety increase as the distance from the toe of the slope increase.

There are advantages and disadvantages for the finite element method and the limit equilibrium method. Good engineering practice is still needed when perform slope stability analysis.