Influences of Hydrodynamic Force on Deep Relaxation Rockslide in Cold and Arid Areas of Langjia Reservoir in China

Abstract

Abstract This research took the Langjia landslide in Qinghai Province of China as an example to explore the failure mechanism and mode of deep relaxation rockslide at cold and arid areas of the plateau under the influence of temperature difference, rainfall. Studies showed that deep relaxation tension cracks are the main precondition of the occurrence of the landslide, and the main triggering factor was the strong weathering and disintegration of argillaceous cemented conglomerate on sliding surface. Affected by rainfall, snow melting, and temperature, the water trapped in tensile cracks froze to ice in winter to accelerate the development of cracks and melt into water in spring and summer to accelerate the weathering process. The process led to forming a sliding surface of mud rock with gravel by weathering the argillaceous cemented conglomerate along the cracks, which was confirmed by field investigation after occurrence of the landslide. For this special failure type, calculation formula on considering rolling friction, sliding friction, and bottom shear stress was proposed, and the influence of shear stress on sliding surface on landslide stability under the seepage caused by rainfall and summer melt water when landslide occurred was discussed. The calculation results of three-dimensional numerical simulation and improved Sarma’s method on considering the hydrodynamic action on relaxation slope stability are consistent with the actual situation.