Abstract: Regarding the problem of instability of water-rich slopes in open-pit mining areas under the influence of rainfall and groundwater，based on the on-site hydrogeological conditions and slope struc⁃ ture，combined with the Van Genuchten saturated-non-saturated seepage model，the ABAQUS finite ele⁃ ment software was used to conduct the seepage-stability coupling analysis under conditions without drain⁃ age holes（24-hour continuous heavy rainfall）and with drainage holes（48-hour continuous heavy rain⁃ fall）. At the same time，a time-series comparative analysis of the pore water pressure and displacement fields of different characteristic surfaces was carried out. The results show that ① under the condition with⁃ out drainage holes，the average pore water pressure increased by approximately 225 kPa，and the maxi⁃ mum equivalent displacement reached 22.62 cm.② After setting up drainage holes，the pore water pres⁃ sure generally decreased by approximately 155 kPa，compared with the condition without drainage holes， it decreased by approximately 380 kPa on average，the maximum equivalent displacement decreased by 35.67%，the maximum displacement in the X direction decreased by 56.31%，and the displacement in the Y direction remained basically stable.③ The drainage holes caused the pore water pressure to rapidly de⁃ crease and stabilize within the first 8 hours，significantly slowing down the deformation development rate of the slope.④ The peak displacement of the top node decreased by 31.85%，effectively inhibiting the rapid instability caused by rainfall. The drainage holes have a significant effect in reducing pore water pressure and slowing down the deformation rate，improving the overall stability of the slope. The provided analysis method can provide certain theoretical basis and technical reference for the slope protection design under similar hydrogeological conditions of mine water.

Key words: rainfall infiltration, slope stability, pore pressure, drainage hole