Study on slope stability considering first-order linear strain-softening theory

Abstract

Under the action of continuous rainfall or excavation unloading, the strength index of soil deteriorates, but most of the current slope stability calculations directly regard it as a constant. To approach the real failure mode of slope instability, based on the Swedish slice method and the first-order linear strain-softening theory, this paper proposes a new method for slope progressive failure analysis, deduces the limit equilibrium expression of the strain-softening slope, and obtains the safety factor under the corresponding damage progress. Through the analysis of simulation examples, the feasibility of the slice-softening method is illustrated, and the calculation results show that the safety factor in the progressive failure process not only depends on the failure mode and strength parameters of the slope but is also closely related to the softening modulus of the rock and soil mass. At the same time, by comparing and checking the actual cases of the Danba landslide, it is confirmed that there are different attenuation coefficients for its strength index, that is, the attenuation coefficient of cohesion is greater than the friction angle. From theory to application, the finally obtained slice-softening method not only considers the strength degradation effect of rock and soil mass under the action of rainfall and the gradual development of sliding surface but can also effectively serve the stability analysis of slope under the background of practical engineering and provide guidance and suggestions for the prevention and treatment of landslides.

Keywords

• slope stability analysis
• strain-softening theory
• swedish slice method
• progressive failure