Abstract: Understanding how rainfall and reservoir water-level fluctuations influence slope seepage fields and stability is essential for preventing landslides and ensuring the safe operation of reservoir infrastructure. Based on a reservoir engineering project, a two-dimensional numerical model of a representative reservoir cross-section was established to investigate the coupled effects of rainfall and water-level rise and fall on pore-water pressure distribution, volumetric water-content variation, and the evolution of slope safety factors. The results indicate that during rainfall and rising water-level conditions, the phreatic line migrates from both the slope crest and toe toward the slope interior until full saturation is reached. When the reservoir water level declines, the phreatic line gradually lowers. Rising water levels increase pore-water pressure and volumetric water content within the soil, leading to a higher slope safety factor, whereas falling water levels reduce pore-water pressure and volumetric water content, resulting in a decreased safety factor.

Key words: Rainfall, Water Level Fluctuations, Stability, Numerical Simulation