Response patterns of dynamic water pressure-induced landslides in the Three Gorges Reservoir area to rainfall: A case study of the Bazimen landslide

ObjectiveThis study aims to explore the response patterns of dynamic water pressure-induced landslides to rainfall. MethodsTaking the Bazimen landslide in the Three Gorges Reservoir area as an example, this study systematically investigated the influence of rainfall on landslide deformation by integrating geological survey data, correlation analysis, and finite element numerical simulation, revealing its response patterns to rainfall and deformation mechanisms. ResultsThe results showed that fluctuations in reservoir water level and rainfall were the main driving factors of the deformation of the Bazimen landslide. The impact of rainfall on landslide deformation was manifested as follows. During the reservoir water level falling stage, rainfall replenished the internal water head of the slope, further enhancing the effect of dynamic water pressure and significantly aggravating slope deformation. During the reservoir water level rising stage, rainfall infiltrated into the rear edge of the secondary sliding zone, which caused an increase in pore water pressure; this in turn triggered deformation at the rear edge of the landslide and further led to overall deformation of the landslide. Adequate rainfall was the main triggering factor of landslide deformation during the reservoir water level rising stage. The landslide deformation exhibited a certain lag, with a lag time of about 20 days for deformation caused by reservoir water level drawdown and 9 days for deformation caused by rainfall. The attenuation degree of the landslide stability coefficient (1.029) under conditions of long-duration continuous rainfall was higher than that of the coefficient under conditions of rainstorm (1.039). ConclusionThe research findings deepen the understanding of the deformation mechanisms of dynamic water pressure-induced landslides and can provide insights into the early warning and prediction of such landslides