Centrifuge modeling test on reactivation of ancient landslide under sudden drop of reservoir water and rainfall

During the normal operation of the Huangdeng Hydropower Station's reservoir, many tensile cracks were observed on the surface of the bank slope below the elevation of 1805 m along the highway, causing significant damage to local residents' production and lives. On-site geological investigation, surface and inclinometer displacement monitoring were carried out, and the deformation characteristics of the Cheyiping landslide were analyzed. A controllable intensity rainfall simulator and a reservoir water level variation simulation system were designed in our laboratory. The lower section of the highway along the river in Cheyiping small village was chosen as the prototype, and a centrifuge model test of the reactivation of the Cheyiping ancient landslide induced by rainfall and reservoir water level fluctuations was performed. The characteristics of landslide deformation, pore water pressure, and earth pressure variation under the influence of rainfall and reservoir water level changes are investigated. The thorough analysis revealed that, even if the sliding surface is not deep, the sudden drop in reservoir water level remains the primary controlling factor of slope sliding. Because the permeability of the deposit is low, rainfall has a minor impact on this ancient landslide. The experimental results can be used to guide slope prevention and reservoir management in the Huangdeng Reservoir area.