Simplified method for three-dimensional slope stability analysis based on rigorous limit equilibrium

A simplified procedure is presented for calculating the factor of safety of a slope with a 3-D slip surface, which satisfies all the six equilibrium conditions for the 3-D sliding body. By assuming an initial normal stress distribution on the 3-D slip surface which is then modified by a polynomial function involving five correcting parameters, the six equilibrium equations are established with a prescribed value of factor of safety, which is linear with the five correcting parameters as well as the horizontal seismic coefficient K-c. An iterative procedure is proposed for determining the factor of safety with a prescribed value of K-c, and ensuring that the normal stresses are positive on the whole slip surface. The method is suitable for analyzing 3-D slope stability, especially with unsymmetric 3-D shapes, and its application in practical engineering is given, which demonstrates the effectiveness of the present method.