Slope Stability Analysis Considering Different Contributions of Shear Strength Parameters

Abstract

From the perspective of the mechanical mechanism of slope failure, cohesion c usually plays a different role with friction φ in sliding resistance, which indicates the distinct weights of their reduction factors Fsc and Fsφ to the overall safety factor of slope Fs in the double strength reduction method (DSRM). This study primarily introduced the equivalent influence angle of slope θe, for which c and φ share identical contributions to the safety factor, and investigated its influencing factors, which turns out that θe shows an increasing trend with an increase of slope weight H or slope height γ, but the increasing rate is decreasing. Subsequently, an equivalent influence angle chart was plotted as an effective and advantageous approach to locate the specific value of θe for a given slope. On this basis, the shortest reduction path method was utilized to calculate Fsc and Fsφ, and the stability contributions of c and φ were quantified by the different weight coefficients of Fsc and Fsφ to Fs. The specific weight coefficient could be solved by the correlation between slope angle θ and corresponding θe, thereby developing a new definition of Fs. Ultimately, a modified double strength reduction method was achieved, which was compared with other DSRMs and verified by existing slope examples.