Deformation Mechanism and Predictive Modelling of Reservoir Bank Landslides: Effects of Rainfall Variation and Fluctuations in Reservoir Water Level

Landslides in the Three Gorges Reservoir area are strongly influenced by rainfall variation and reservoir water level fluctuations. This study takes the Shengjibao landslide as a case study to investigate how these hydrological factors affect slope deformation. Laboratory direct shear tests were conducted to determine the shear strength characteristics of the sliding‐mass soil under different moisture contents. The test results were then incorporated into Geo‐Studio simulations to evaluate variations in the safety factor under multiple rainfall and reservoir drawdown scenarios. In addition, a displacement prediction model integrating rainfall and reservoir water level indicators was developed to identify the relative effects of different triggering factors. The results show that rapid reservoir drawdown exerts a more pronounced influence on slope stability and cumulative deformation than rainfall. The proposed framework improves the understanding of the hydro‐mechanical behaviour of reservoir‐bank landslides and provides support for early warning and disaster mitigation in reservoir areas.