Model Test and Numerical Analysis on the Deformation and Stability of a Landslide Subjected to Reservoir Filling

Reservoir filling can affect the landslide stability and cause the landslide deformation within the reservoir area. In this paper, a physical model test and a series of numerical analyses were combined to investigate the landslide deformation and stability under reservoir filling. The surface deformation, deep displacement, and pore water pressure were recorded during the physical model test. In the model test, the increasing period of the pore water pressure inside the landslide is proposed to be a critical period for the landslide subjected to the reservoir filling. During this period, large landslide deformation occurred. The numerical analyses show that a greater factor of safety (FOS) appeared under a higher water level rising rate or a lower permeability coefficient during the water level rising stage when other variables are fixed, due to the domination of the reservoir buttressing effect which can increase the landslide resistance. During the reservoir maintaining stage, the reservoir water infiltrated into the landslide continuously to cause the matric suction dissipation and pore water pressure increase, which reduced the landslide shear strength and then decreased the landslide stability.