Effect of water level fluctuation and its rate on the response of deposits on a reservoir slope: flume experiment, case monitoring comparison and failure mechanism

Frequent threats from landslides in reservoir areas have caused a research boom in academia due to the commissioning of the Three Gorges Project and the continued promotion of hydropower development in southwestern China. In this study, a series of analyses, mainly flume experiment, were conducted on reservoir slope deposits with large landslide potentials. This article focuses on validating the deformation and hydrological response process of the experimental re-enactment under different changing water level conditions and comparing them to real case observations and monitoring. The experimental results provide a basis for the systematic formulation of the mechanism of slope deposit failure in the reservoir area. The occurrence of landslides on slope deposits is usually caused by the accumulation of multiple phases of deformation rather than one phase of deformation. The deformation of the slope deposits is mainly in the form of erosion collapse at the front edge and shearing-tension cracking at the rear edge. These are directly caused by the large increase in the water level during the impoundment period and the rapid drawdown of the water level or the coupling of continuous strong rainfall and water level drawdown during the operation period. In this case, the loss of fine particles, the seepage force, and the increase in pore water pressure all play an important role. In this study, we hope to provide some scientific insights into the warning and mitigation of slope mounding hazards in reservoir areas.