Impact of water level fluctuation on the reservoir landslide stability

Abstract

Taking Sidaoqiao landslide in Wushan County in Three Gorges Area as an example, this paper explore the impact of reservoir water level rising and falling at different rate on the stability of typical gravel soil accumulation landslide by establishing the landslide seep model and slope model with the Seep module and Slope module in Geostudio and calculating the landslide seepage field and stability coefficient. Results showed that the impact of reservoir water level fluctuation on landslide stability was controlled by several factors such as hydrodynamic pressure, hydrostatic pressure, uplift force, variation in physical–mechanical properties (the value of c, φ etc.). When the water level fluctuates at a high rate, before the stability coefficient reaches the maximum value, the landslide stability is mainly affected by the hydrostatic pressure; while after the maximum value, with water further infiltrating into or draining out of the slope, it is mainly affected by the variation in physical and mechanical properties and the uplift force. When the water level fluctuates at a lower rate, the pore water pressure, uplift force and physical and mechanical properties are the dominant factors.