Establishing a reasonable rainfall infiltration model is crucial for understanding the mechanisms of rainfall-induced slope failures and for preventing and controlling landslide disasters. Currently

numerical solutions to the Richards equation and the Green-Ampt model are commonly employed to analyze rainfall infiltration in slopes. However

numerical solutions to the Richards equation often encounter convergence issues

while the Green-Ampt model suffers from relatively low accuracy and an inability to account for non-uniform initial soil moisture distribution and pore water redistribution. In this study

we propose a spatiotemporal approximation method based on the Green-Ampt model for analyzing rainfall infiltration in slopes. This method involves discretizing the slope stratum into multiple spatial elements along the depth and dividing the rainfall event into multiple time intervals. Using this method

we investigate the changes in seepage

stability

and reliability of heterogeneous infinite slopes under rainfall infiltration. The results show that

compared to numerical solutions of the Richards equation

the proposed method is a robust and accurate approach for analyzing rainfall infiltration

with no convergence issues. Additionally

ignoring the pore water redistribution process can lead to underestimating the probability of slope failure and misidentifying the location of the critical sliding surface. The research outcome can provide theoretical support for rainfall infiltration analysis of complex slopes and prevention and control of rainfall-induced shallow landslide disasters.