Model Test and Numerical Simulation of Slope Instability Process Induced by Rainfall

Abstract

Due to rainfall infiltration, slope instability becomes frequent, which is the main reason for landslide disasters. In this study, the stability of slope affected by rainfall was analyzed using an indoor model test and geo-studio simulation method, and the variation law of phreatic line, seepage field, the most dangerous sliding surface, and safety factor with time were studied under rainfall infiltration. Research results showed that under the effect of rainfall, the slope failure presented a typical traction development mode. With the increase of time, the phreatic line of the slope kept rising, the water head keeps increasing, the seepage depth in the slope became deeper, and the slope stability worsened until the slope was damaged. The water head height decreased gradually from the slope left boundary to the right, and the water head width decreased gradually. The soil at the slope back edge was damaged, and the sliding soil accumulated at the slope foot, forming a gentle slope, which increased the shear strength of the slope, making the slope finally reach a stable state. In this process, the overlying soil changed from an unsaturated state to a saturated state, the pore water pressure and soil pressure increased, and then the slope was damaged, both of which decreased. Under high rainfall intensity, the slope was damaged, the soil in the slope was rapidly saturated, and the time required to produce the sliding area was short. When the rainfall intensity was the same, the smaller the slope angle was, the smaller the safety factor was. When the slope angle was the same, the greater the rainfall intensity was, the smaller the safety factor was.