Research On Failure Criterias And Critical Slip Surfaces Of Rockmass Slope

How to judge the slope's state with FEM based on shear strength reduction methods, stability or instability based on the results of FEM is a key problem. There are three main criterias for evaluating instability: the convergence of equation's solution, the abruptness of the displacement or deformation at a certain characteristic location and the connectivity of plastic zone. In order to determine the safety factor of slope, in the presence of FEM software ANSYS, three examples are analyzed by applying the three criterias, and then the results from the various criteria are compared with the others.Based on the abruptness of the displacement or deformation at a certain characteristic location, the slope's safety factors are determined by the change points of the relation curves of the strength reduction factors with the maximal strain energy, the maximal plastic strain and the deformation of characteristic points. According to the characteristics of the connectivity of plastic zone, shear strain rate, plastic strain energy of element and plastic strain vector distribution of slope, the determination of critical slip surfaces are discussed.Various factors of slope stability are sensitively analyzed. Combined with the example, the influence of calculation model (including range, boundary conditions, meshing density etc.), failure criterion, reduction mode of material parameters, flow rule and failure criteria on safety factor and latent slip surface are discussed. Therefore, some advices are presented.Taking a hydropower station slope as an example, the determination of safety factor and critical slip surfaces are discussed by applying the various failure criterias, and then the excavation and support measures are given by the engineering conditions. After the comparison of the above results and the results of limit equilibrium method and disturbing energy method, the determination feasibility of safety factor and critical slip surfaces are verified. It provides basis for more applications of the determination method in slope stability analysis.