Laws of evolution of physico-mechanical parameters along the elevation of landslides under the effect of rainfall

Abstract

To investigate the impact of rain on the physical and mechanical components of accumulation body landslides, a physical model was created in the western of China. Rainfall is a primary factor in such landslides. By simulating typical rainfall effect, samples were taken at different elevations of the accumulation body physical model, and permeability and direct shear tests were carried out. The evolution of mineral content, porosity, permeability coefficient and shear strength parameters along the elevation are analyzed in detail. The results show that the porosity at the top of the slope surface is 2.2 times that at the bottom of the slope surface, and the content of SiO₂ and Al₂O₃ representing fine particles such as river sand and clay increases by about 7% and 3%.The permeability coefficient and internal friction Angle of accumulation body increase gradually with the increase of elevation, but the c value of cohesion shows the opposite law and gradually decreases. The permeability coefficient, internal friction Angle and cohesiveness of slope surface change more obviously than that of slope interior. Combined with the quantitative analysis of parameters and the observation of phenomena in the test process, it is shown that the runoff and seepage of rainfall promote the migration and accumulation of fine particles to the low elevation of the slope. The research process and result are of great significance to the stability analysis of accumulative landslides under rainfall conditions.

Keywords

rainfall effect / accumulation body / physical model test / elevation / parameter evolution