Study on Seepage Characteristics and Stability of Core Dam Under the Combined Action of the Variation of Reservoir Water Level and Rainfall

To study the influence of the variation of reservoir water level and rainfall on the seepage characteristics and stability of the core dam, considering the coupling effect of seepage field and stress field, finite element simulation of seepage and stability of dam slope when the core dam encounters the variation of reservoir water level and rainfall was carried out based on the unsaturated seepage principle, different rainfall intensities, different rainfall types and different variation rates of reservoir water level were selected for finite element simulation. The results show that: The variation rate of water level mainly affects the time when pore water pressure tends to be stable. The rainfall intensity and rainfall type mainly affect the pore water pressure in the upper part of the dam, and the higher the rainfall intensity, the more drastically the pore water pressure changes in the upper area of the core dam. Rainfall type and rainfall intensity are the main factors that affect the safety factor of the downstream slope of the core wall dam, but have little effect on the safety factor of the upstream slope. When the safety factor of the downstream dam slope tends to be stable, the order of the safety factor of different rainfall type is: forward type > = center type > average type > post-peak type. Whether the water level rises or falls, rainfall will reduce the safety factor of downstream dam slope. The results of this study provide a reference for correctly understanding the seepage and stability law of the slope of core dam and a reference for risk analysis and emergency management when the core dam encounters extreme working conditions.