Non-Equal Strength Reduction Analysis of Soil Slopes Considering Progressive Failure

A non-equal strength reduction technique for slope stability analysis is developed that considers the progressive failure characteristics of soils with strain-softening behavior. The method assumes that the soil’s cohesion and friction angle decrease from peak to residual strength along different paths during shear failure. A relationship between the reduction factors of the cohesion and friction angle is derived, and a calculation code is compiled based on a finite difference program. Sensitivity analysis shows that the attenuation interval coefficient has little effect on the calculation results. The factor of safety obtained by this method lies between the traditional strength reduction and limit equilibrium methods. Finally, the selection of failure criteria in slope limit analysis using numerical modelling is discussed.