Evaluation of minimum factor of safety in slope stability analysis

Abstract

This paper explores the feasibility of using optimization methods to search for the minimum factor of safety in slope stability analysis. The routine procedure includes comparing a number of admissible surfaces that are basically selected by random searches. Low efficiency and unreliability are the problems commonly encountered.Optimization methods allow a mathematically rigorous and reliable search for the minimum factor of safety and its associated "critical slip surfaces." This paper employs simplex, steepest descent, and Davidon – Fletcher – Powell (DFP) methods. The results of a number of test problems, in conjunction with closed-form and grid search solutions, showed that all the above-mentioned methods can provide reasonable results. Case history analyses supported the feasibility of the methods. Modifications to the DFP method were found to be essential for successful implementation of the minimization procedure. Key words: slope stability, landslide, analysis, limit equilibrium, interslice forces, factor of safety, spline function, optimization methods, case history.