Unified Formulation for Two Dimensional Slope Stability Analysis and Limitations in Factor of Safety Determination

A new unified formulation of two dimensional limit equilibrium slope stability analysis method is developed in this paper. Based on the present formulation, Bishop’s simplified Method, Janbu’s simplified and rigorous methods, Lowe and Karafiath’s method, Corps of Engineer’s Method, Load transfer factor method, Blocking equilibrium Method, Spencer’s Method and Morgenstern-Price’s method and Leshchinsky’s method can all be derived as a special case of the more general formulation. The authors have also investigated into several interesting examples in the determination of factor of safety. To solve for the factor of safety under difficult problem, Gauss-Newton method with a line search step selection strategy is proposed.