Back-analysis of slope failures by numerical techniques

A method of defining strength parameters from slope failures is presented in this study, based on combining finite element and optimization analyses. The strength reduction technique is used to determine the shear strain field. The slip surface is then obtained from shear strain contours by extracting the maximal strains in several vertical lines. This surface is used for the optimization process when comparing to the observed failure surface. The optimization algorithm computes the sensitivity matrix with fix increments to avoid stationary values of the objective function. Two illustrative examples are presented, one considering a simple homogenous slope and the second compose of a two-layered model. The results of the analysis show that the proposed technique is efficient to determining soil parameters from slope failures by retaining the advantages of finite element slope stability analysis.