Experimental study on slope collapse characteristics of granite residual soil slope under heavy rainfall

The granite residual soil in southeast coast area is selected as the representative soil sample and the simulation test schemes of rainfall triggered landslide are designed with the slope gradient and the rainfall intensity as their control variables. Then the heavy rainfall simulation experiment of slope models with four different gradients are performed under four kinds of different conditions, i.e. heavy rain, rainstorm, heavy rainstorm, extreme rainstorm, and the influence characteristics of rainfall intensity and slope gradient on slope slumping destruction are studied. The results show that the greater rainfall intensity is, the larger the slide block size of collapse is and the more concentrated the scope of damage is, while more obvious the trend of deep or shallow overall damage of slope. In addition, the extent of slope damage is enhanced and the less time needed for soil cracks appear and slope slumping destruction at the same time. With the slope gradient increases, the failure modes of slope gradually become scattered collapse from landslide sliding and the rainfall duration of slope sliding damage is reduced. The research results have important theoretical and practical significance for disclosing the rule of residual soil landslides and other geological disasters triggered by heavy rainfall.