Finite element slope stability analysis by shear strength reduction technique

ABSTRACT A shear strength reduction technique for finite element slope stabilityan alysis has been developed by the authors. An important orginal point in the proposed method is that the slope failure is defined according to the shear strain failure criterion. The aim of this paper is to verify the shear strength reduction technique for the finite element slope stability analysis. Are presented the detailed background behind the shear strength reduction technique, the elucidation of the physical meaning of the critical shear strength reduction ratio in regard to the total shear strain and shear strain increment for both embankment and excavation slopes and its practical application to a field test on a reinforced slope cutting. As the results, the critical shear strength reduction ratio agrees with the safety factor by the Bishop’s method if total shear strain is used for analyses of embankment slopes. In the case of the natural excavation slopes, in which total shear strain is difficult to be assessed, the safety factor can be related to the average of the local safety factors along the failure slip surface obtained by the shear strength reduction technique. The predicted behavior of the reinforced slope cutting agrees with the field test data and site observation. Agreement between the shear strength reduction technique and a modified Fellenius’ method is satisfactory. Consequently, applicability of the proposed method to practical design works is demonstrated.