Research on the deformation characteristics of Sanmendong landslide and the correlation of hydrodynamic action

Abstract

Studying the formation mechanisms and influencing factors of typical regional landslides is a crucial step in landslide control and disaster prediction. The mechanism of formation and the influence of hydrodynamic factors on accumulated landslides in the Three Gorges Reservoir have always been a focus of attention. Although rainfall and reservoir water level factors interact with each other, refining the impact areas and characteristics of these two factors will be beneficial for future research on accumulated landslides in the Three Gorges Reservoir area. Taking the Sanmendong landslide as an example and relying on its geological background and professional monitoring data, this study employs gray correlation analysis to analyze the sensitivity between changes in hydrodynamic factors and changes in landslide safety factor. It discusses the regions affected by rainfall and the descending speed of the reservoir water level under different conditions, as well as the changing patterns of data. The ILF-FFT landslide prediction model is utilized to study the relationship between real monitoring data of the Sanmendong landslide and fluctuations in hydrodynamic factors, obtaining the weight coefficients of hydrodynamic factors in the model and separating the fluctuation curve under the influence of rainfall and reservoir water level fluctuations. A comparative analysis of the contribution of hydrodynamic factors to the deformation of the Sanmendong landslide is conducted. The results indicate that the overall deformation of the Sanmendong landslide is more sensitive to rainfall factors, and as the descending speed of the reservoir water level increases, its sensitivity to landslide deformation will also increase. The local deformation of the landslide toe is greatly affected by the factors of reservoir water level descent, and with the increase of the descending speed of the reservoir water level, the correlation results also increase. It is important to note that there is a sudden change in the correlation results at a descending speed of 1.0 m/d in the local stability analysis, which is related to the most dangerous sliding surface identified in the simulation calculation and requires special attention during the process of reservoir water level descent. Furthermore, the deformation of the landslide toe in Sanmendong is greatly affected by the descent of the reservoir water level, while the deformation of the landslide head is more influenced by rainfall factors.