Global　warming　has　caused　frequent　occurrences　of　extreme　rainfall　events　worldwide.　Studying　the　rainwater　infiltration　in　monolithic　soil　covers　(MSCs)　and　associated　slope　stability　under　heavy　rainfall　presents　practical　significance　for　landfill　management.　This　study　established　an　analytical　solution　for　rainwater　infiltration　in　MSCs　during　heavy　rainfall　assuming　that　the　soil　hydraulic　properties　follow　exponential　forms.　The　analytical　solution　was　used　to　calculate　the　factor　of　safety　(FOS)　of　MSCs　after　the　verification　with　numerical　simulations.　It　is　found　that　the　FOS　for　the　potential　slip　surface　at　the　cover　bottom　remained　the　lowest　during　and　after　heavy　rainfall.　The　percolation　and　FOS　might　present　pronounced　“lag　effects”,　meaning　that　the　maximum　percolation　rate　and　minimum　FOS　occurred　after　heavy　rainfall.　A　parametric　study　was　conducted　to　reveal　the　influencing　factors　on　the　hydraulic　response　and　slope　stability　of　MSCs　based　on　the　analytical　solution.　Relevant　results　demonstrate　that　the　hydraulic　performance　and　slope　stability　could　be　improved　by　decreasing　soil　saturated　hydraulic　conductivity,　increasing　soil　desaturation　coefficient,　and　lowering　water　level　in　landfills.　The　results　also　reveal　the　existence　of　a　threshold　of　soil　saturated　hydraulic　conductivity　(1　×　10−8　m/s　for　this　study)　for　controlling　the　hydraulic　performance　and　slope　stability　of　MSCs.　Furthermore,　the　analytical　solution　was　applied　to　determine　the　rainfall　intensity–duration　threshold　curves　of　MSCs.　The　results　indicate　that　the　obtained　curves　of　MSCs　satisfied　exponential　forms.　This　study　provides　an　effective　tool　and　valuable　guidance　for　the　design　and　maintenance　of　MSCs.　©　2025　The　Author(s).