The normal operation of the Yulangpei tailings reservoir is affected by landslide stability. In this paper, taking the main and side slopes near the dam bank of the Yulangpei ditch as an example, the water–soil coupling theory is applied to comprehensively evaluate the reliability of the side slopes of the tailings reservoir. Grading and seepage prevention (GSP) measures and the suction of the substrate are considered, as well as the infiltration of different rainfall and reservoir water levels. We numerically simulate the typical three forms of side slopes under the coupling conditions and conduct a reliable and comprehensive evaluation of the tailings reservoir side slopes. This study shows that the analysis of condition 1 indicates that the factor of safety (FS) of the bank slope shows a lag effect and that GSP can improve the FS of the slope, but not significantly for the main slope. The analysis of condition 2 shows that the weakening effect increases with the intensity of rainfall during the rainfall process, while the FS rebounds when the rainfall stops. The initial stability of the bank slope under different conditions improves after the GSP measures, but the main slope is more sensitive to the changes in rainfall and water level. The analysis of condition 3 shows that the overall trend of FS and displacement of the main slope shows a small decrease followed by a sharp increase. The FS of the side slope is negatively correlated with the change in total displacement, with a general trend of a slight increase followed by a sharp increase. After GSP, the overall FS of the main slope increases by about 3% and the total displacement decreases by about 87%, and the overall FS of the side slope increases by about 41%, while the total displacement decreases by about 66%.

The normal operation of Yulangpei tailings reservoir is affected by landslide stability. In this paper, taking the main and side slopes near the dam bank of the Yulangpei ditch as an example, water-soil coupling theory is applied to comprehensively evaluate the reliability of the side slopes of the tailings reservoir. Grading and seepage prevention (GSP) measures and the suction of the substrate are considered, as well as the infiltration of different rainfall and reservoir water levels. We numerically simulate the typical three forms of side slopes under the coupling conditions and conduct a reliable and comprehensive evaluation of tailings reservoir side slopes. The study shows that under six reservoir water level changes, the factor of safety (FS) of the bank slope shows a hysteresis effect. According to nine rainfall infiltration conditions and during rainfall, the greater the rainfall intensity, the greater the weakening effect. When rainfall stops, the FS rebounds. After GSP measures, the initial stability of the bank slope under different conditions is improved, but the main slope is more sensitive to changes in rainfall and water levels.