Sun Chai Lee

Date of Graduation


Document Type



This investigation was conducted to determine the applicability of the limit equilibrium methods of slope stability analysis. Six of the most widely used methods of slope stability analysis were selected from methods which satisfied different equilibrium conditions. An examination of the differences among these methods was undertaken. Through investigation of the mechanics involved in the analysis. Parametric studies were also conducted to establish quantitative trends in the resulting factors of safety. Results of the investigation indicate that: (1) The most significant factor in the stability analysis of slopes is the shear strength parameters of soil, i.e., cohesion and angle of friction. (2) The Ordinary Method of Slices may be applied to total stress analyses of circular failure surfaces; however, it is not recommended for effective stress analyses with high porewater pressures. It is useful for preliminary design studies due to its moderate amount of conservatism. (3) The Simplified Bishop method is the most preferable method for analyses of circular shear surfaces. It gives acceptably accurate results as compared to more exact solutions which require considerably more time and effort for obtaining a solution. (4) For non-circular failure surfaces, the Simplified Janbu method may be used for preliminary design studies, but the Spencer method is the most preferable although it requires more time and effort to obtain a solution. (5) The force equilibrium methods give results which are unconservative. They are suitable for non-circular failure surfaces. The Corps of Engineers method is the least suitable of the force equilibrium methods since it gives higher factors of safety (less conservative) than the Lowe and Karafiath method.