Deformation and stability analyses of a near-dam rocky slope and its potential landslide-generated wave threats

Occurrence of a reservoir landslide and its potential secondary hazards near a dam can result in significant losses and casualties, such as those that resulted from the Vajont landslide. In this study, a cataclinal rock slope in the Maoergai reservoir was taken as a case to study the characteristics of the gravitational deformation process and to analyse the potential threat. The stability of the rock slope was analysed using the limit equilibrium method, and the potential landslide movement and subsequent waves were simulated. Results indicated that lithology, geological structure, reservoir water-level changes and artificial activities all play an important role in large deformations of rock slopes that are characterized by a combination of bending–toppling and, principally, shear slip. Pre-calculations of potential threats indicated that the impact of a landslide wave would be greater at dead water levels than at the normal water level and could result in the blockage of the inlet to the water-diversion structure on the opposite right bank. These findings provide implications for the control of reservoir rock slopes: (i) serious attention should be paid to the influence of water on rock strength in the early investigation of geological disasters; and (ii) infiltration must be prevented during water-level rise. Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes