Pseudostatic Stability Analysis of Rock Slopes Using Variational Method

Abstract

In this paper, a rectilinear slope of homogenous rock is analyzed by using the variational method. The strength of the rock medium is assumed to be governed by the Hoek–Brown failure criterion. Although the variational method is developed within the framework of limit equilibrium method, however, neither the shape of the critical slip surface (kinematical assumption) nor the distribution of normal stresses along the slip surface (statical assumption) is required to assume. The aim of this paper is to obtain critical slip surface and the corresponding critical factor of safety (Fs) for different combinations of (i) slope geometries (slope angle, β and height of slope, h), (ii) rock properties (Geological Strength Index, GSI, non-dimensional strength parameter for intact rock, mi, disturbance factor, Df, and uniaxial compressive strength of intact rock, σci) and (iii) seismic loading conditions (coefficient of horizontal seismic acceleration, kh). The magnitude of Fs is evaluated uniquely by implementing certain necessary constraints on the slip and the slope surfaces and optimizing the functionals generated from resisting and driving moments. The failure surfaces drawn for several cases provide an insightful observation of the influence of different (a) material properties, (b) slope geometries and (c) seismic conditions.