Abstract:Rainfall is one of the main factors leading to slope instability. In this paper, taking the slope of a phosphate mine dump in central Yunnan as an example, the influence of continuous rainfall on the stability of the 6 # dump slope is studied. Based on the theory of saturated-unsaturated soil seepage, the dynamic change, deformation failure, and stability of saturated-unsaturated seepage field under continuous heavy rainfall are simulated and calculated by using the indoor unsaturated soil static triaxial test combined with GeoStudio finite element method. The results show that the greater the matrix suction in the initial stage of rainfall, the higher the safety factor of the slope. However, after 12 hours of rainfall, the safety factor is basically not affected by the matrix suction and is basically consistent with the theoretical calculation results. The overall stability of the slope is good, which is consistent with the actual situation of the dump. When rainwater infiltrates continuously, the plastic deformation area of multi-level bench dump is mainly concentrated at the foot of the slope. The simulation results are generally reliable, which can provide a reference for the safety production of multi-level bench dumps in continuous heavy rainfall areas and mine dumps in central Yunnan.