Soil-Slope Stability considering Effect of Soil-Strength Nonlinearity

To estimate the factor of safety of soil slopes, the discretization technique is widely used to generate the critical slip surface under the linear Mohr-Coulomb failure criterion. However, the strength envelope of almost all soils has the nature of nonlinearity. This study develops a novel approach to calculate the factor of safety of soil slopes when the soil strength follows the nonlinear yield criterion. First, the numerical simulation is used to obtain the magnitude and the coordinate of minor principal stress. Then, the equivalent strength parameters are calculated by combining with the nonlinear failure criterion. Finally, slip surface is generated by the discretization technique and the factor of safety is derived on the basis of the upper bound theorem. The elastic stress analysis method of numerical simulation is used to obtain the stress distribution, and its validity is demonstrated by comparing the results derived from the elastic stress analysis and those from the elastic-plastic stress analysis. To further show the validity of the proposed method, the presented results are compared with those using GEOSLOPE software, which is a limit equilibrium method, and with those of previously published results. Based on the comparisons, the proposed method is an effective technique to calculate the factor of safety of soil slope under the condition of nonlinear failure criterion. The examples indicate that the proposed method has potential applicability in obtaining the stability of slope in layered soils.