Geometrical profile of cohesive-frictional soil slopes for optimal stability

Abstract

In this study, finite element method with strength reduction technique is employed to study the stability of slopes with non-straight line profiles comprises three segments. According to this method, the strength parameters are reduced until the slope becomes on the verge of failure. A software called (Optum G2) is used to analyze the geometrical and mechanical parameters. The effect of the geometrical shape of the slope with specific limitations on the factor of safety (FOS) has been investigated to find the corresponding profile configuration that provides maximum stability. The profile (slope face geometry) has been divided into three straight lines (segments) with different lengths. The study involved the soil cohesion (c), angel of internal friction (∅) and the angle of the imaginary straight line linking the slope toe with slope crest (β) called herein slope inclination. The main results showed that using the three segments facing profile can increase the factor of safety (FOS) by up to 15% in comparison with the corresponding slopes of straight-line profile. Design charts has been introduced to be utilized by engineers and practitioners to obtain the geometrical parameters for the optimal profile as well as the expected improvement percentage in factor of safety.