Modelling of Critical Slip Surface Geometry for Sustainable Slope Stability Analysis

Knowledge of the critical slip surface is essential for slope stability analysis and design of remedial works. The classical analysis for assessing slope stability uses limit equilibrium methods, which impose the shape of the critical slip surface as a circle. In practice, it can be observed that the shape of the critical slip surface is not circular. In this study, a methodology was proposed and used to determine the position and shape of the critical slip surface using the results of the finite element method. Four types of regression curves were analysed and compared (circle, damped sinusoid, second-degree parabola and logarithmic spiral) via nonlinear optimization using the least-square method. In addition, these results were compared with those obtained using the limit equilibrium methods (Fellenius, Bishop, Janbu, Morgenstern–Price and Spencer).