(1. MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China；2. Institute of Geotechnical Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China；
3. Wantai Construction Co.，Ltd.，Chongqing，Chongqing 400084，China)
Abstract：A limit equilibrium method that satisfies the three force equilibrium conditions of all columns and three moment equilibrium conditions of total failure mass is proposed，in which the interslice forces are assumed by proposed lateral shear factors and lateral shear distribution functions. The present formulation can be treated as an extension of the 2D Morgenstern-Price? technique. The factor of safety of each row(column) is obtained by solving the force equilibrium equations and the boundary conditions of total failure；then the lateral shear factors are determined by solving the torque-equilibrium equations for total failure mass. All intercolumn forces are taken into account in calculating factor of safety. The direct iterative algorithm is implemented in the program developed by the authors to improve the computational efficiency markedly. The analysis results for two examples indicate that the given ?1，?3，?4 have a small effect on the factor of safety for symmetrical slope and the given ?4 also has a slight effect on the factor of safety for asymmetric slope；and these factors of safety obtained in the new formulation are similar to those in previous studies. It is not necessarily true for some composite slip surfaces that a more simplified formulation will give a lower factor of safety.
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2013, Vol. 32 
