EFFECTS OF STRAIN SOFTENING AND STRENGTH SPATIAL VARIABILITY ON SLOPE FAILURE MOVEMENT BY MATERIAL POINT METHOD

抄録

Landslide and slope failure are a continuous geological process, which should be analyzed through the whole process from pre-failure to post-failure. The transition of slope from stable to unstable conditions involves a major distortion of the soil and a change in constitutive behavior, where the post-peak strength degradation governs the response. Strain softening after soil peak strength is the point of concern through-out the whole analysis process, and its impact deserves to be discussed. In this study, the material point method (MPM) is used to analyze the whole process of slope failure with the strain softening elasto-plastic constitutive law. First, we verify the accuracy and necessity of considering strain softening for the slope stability stage and post-failure stage. In addition, the effects of softening parameters and soil spatial variability on the post-failure process are discussed. The main conclusions are as follows: (1) The strain softening behavior not only affect the slope stability, but also affect the runout characteristics of post-failure slope. (2) The softening stiffness S has no influence on the runout characteristics. (3) The MPM analysis for slope with soil strength spatial variability shows that the distribution of runout characteristics becomes wide due to strain softening.