Evolution trend of reservoir bank landslides driven by numerical simulation and mechanism analysis

Landslide disasters have become frequent in the Three Gorges Reservoir area (TGRA) since the first reservoir impoundment in 2003. This study aims to investigate the evolution of landslide disasters on the reservoir bank by analyzing the influence of reservoir water level (RWL) fluctuations and rainfall, taking the Jiuxianping landslide in the area as an example. Employing finite element numerical simulation methods, in conjunction with in-depth on-site investigations and the analysis of monitoring data gathered between 2016 and 2019, the study successfully replicated the step-up deformation pattern and elucidated the progressive evolution of the Jiuxianping landslide. The results indicate that the seepage within the landslide is primarily influenced by rainfall in the upper part of the landslide, by RWL in the lower part, and by a combination of both in the middle part. The landslide stability is primarily affected by RWL fluctuations, and rainfall further exacerbates the instability. The cyclical effects of RWL and seasonal rainfall account for the progressive deformation of the landslide in stages, consistent with the step-up characteristics observed in the displacement-time monitoring curve. The research results provide a reasonable basis for the follow-up prevention and control of the Jiuxianping landslide and a reference for the deformation and evolution research of other landslides in the reservoir area.