The　in　situ　frost-heaving　(FH)　process　and　characteristics　of　the　shallow　layer　of　a　residual　soil　slope　in　the　intermittently　frozen　zone　were　simulated　by　a　modified　three-dimensional　particle　flow　code　(PFC3D)　model,　of　which　the　mesoscopic　parameters　of　soil　and　ice　particles　were　calibrated　through　the　indoor　experiments.　In　this　model,　the　in　situ　FH　process　was　gradually　achieved　by　expanding　the　volume　of　ice　particles　(divided　into　24　times　of　expansion),　and　the　process　was　terminated　when　the　monitored　porosity　was　stable.　These　countermeasures　avoided　the　stress　accumulation　and　effectively　realized　the　simulation　of　the　in　situ　FH　process.　The　results　found　that　the　displacement　occurred　firstly　and　got　the　largest　final　value　at　the　surface　angle　(SA)　under　the　in　situ　FH　effect,　followed　by　that　at　the　foot,　and　it　gradually　extended　to　the　interior　based　on　these　two　regions.　The　vertical　tension　was　present　at　the　SA,　and　the　major　force　type　in　the　lateral　interlayer　was　pressure.　In　addition,　the　FH　effect　seemed　to　be　strongly　related　to　the　frozen　depth,　and　a　sliding　surface　was　found　in　a　steeper　slope.　Finally,　the　smaller　stone　appeared　to　be　favorable　to　the　slope　stability,　but　it　was　reduced　by　the　larger　stone　to　some　extent.