Dynamic Hydromechanical Behavior of Reservoir Slopes: Seepage and Deformation under Variable Water Level Drawdown

Abstract

Seepage and deformation of a large-scale reservoir slope model under water level drawdown was first studied using the self-developed testing platform. Coupled seepage-deformation finite element analysis was then performed to simulate the dynamic hydromechanical behavior. A parametric study was finally conducted to elucidate the influence of drawdown rate, range, and mode on the seepage and deformation characteristics. When the drawdown rate is over 0.1 m/d, the increase in drawdown rate induces a faster change in pore water pressure and more intensified slope deformation. As the water level is reduced by more than 57%, the lower part of slope is significantly mobilized and the slope is subjected to the larger seepage force, decreasing slope stability and causing greater slope deformation. Under drawdown with the convex (increasing rate), linear (constant rate), and concave (decreasing rate) modes, the degree of saturation, pore water pressure, soil displacement, and slope deformation show the fastest response in the convex mode while the slowest response in the concave mode, and the characteristics of the hydromechanical responses are distinctly different during different modes of drawdown. However, the ultimate slope deformation does not very much in each scenario when the same range of drawdown completes within the same time.

Keywords

reservoir slope / drawdown / seepage and deformation / large-scale model tests / numerical simulations

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