Deformation mechanism of landslide caused by wave scouring considering water level rise

Frequent water level fluctuations arise from the long-term operation of the Three Gorges Reservoir in China has resulted in frequent water level fluctuations, leading to intense wave scouring on the reservoir banks. To reveal the evolutionary process and instability mechanism of landslide deformation caused by wave scouring under water level rise, this study focused on reservoir landslides and surveyed the wave scouring disasters. On this basis, a suite of physical modeling tests was carried out, and the evolutionary process of landslide deformation induced by wave scouring and variations in horizontal earth pressure and pore water pressure were monitored during the tests. The influence of water level rise on wave scouring and landslide deformation is analyzed. The results show that the large deformation of the landslide is caused by the combined effect of reservoir water rise and wave scouring. At a constant water level, wave scouring primarily leads to soil erosion, rendering its influence on landslide deformation negligible, with the erosion rate governed by a decaying exponential function. However, the increase in water level significantly enhanced the erosion ability of waves, expanding the erosion distance by 1.41 times and thus increasing the landslide displacement by 1.27 times. This directly triggers landslide instability. The sequence of landslide deformation processes caused by the combined effects is as follows: soil erosion (deformation brewing stage), shoreline retreat (deformation development stage), water level rise (deformation intensification stage), and bank collapse expansion (landslide failure stage). This study provides a scientific basis for the formulation of landslide control strategies in the Three Gorges Reservoir Area (TGRA).