To reveal the full-process evolution of a building-adjacent cut slope from failure incubation to sliding and deposition under persistent rainfall wetting, and to evaluate the near-field threat posed by sliding-front advance to slope-toe houses, a typical landslide hazard in northeastern Jiangxi was selected as a case study. Based on engineering geological investigation data, an unsaturated two-phase material point method was used to simulate self-weight initialization, rainfall-infiltration-induced failure, and post-failure sliding and deposition. The spatiotemporal evolution of pore water pressure, liquid saturation, horizontal displacement, solid-phase velocity, and cumulative deviatoric strain was analyzed. The main weakened zones, sliding mode, and key evolution stages were identified. Near-field risk was evaluated by comparing the sliding-front advance with the initial clearance between the slope toe and the houses. The results show that an initial hydro-mechanical equilibrium state is formed after self-weight initialization. The shallow part remains unsaturated, whereas the deeper part is nearly saturated. No continuous shear band is formed at this stage. Continuous rainfall at 50 mm/d increases pore water pressure toward 0 kPa and increases liquid saturation. A high-saturation and low-suction weakened zone gradually develops along the interface between residual colluvial silty clay and strongly weathered shale. The slope reaches a critical failure state after 10 d of rainfall. After failure, traction-type sliding is initiated at the slope toe and progressively extends upslope along the soil-rock interface. Horizontal displacement continues to accumulate. Solid-phase velocity first increases and then decreases, showing a single-peak response. Cumulative deviatoric strain progressively expands and finally coalesces. Major sliding, frontal advance, and slope-toe deposition mainly occur within 0-40 s after failure. Based on the hydraulic, deformation, and dynamic responses, the full failure process is divided into two stages: rainfall-infiltration-induced failure incubation and post-failure sliding and deposition. The latter is further divided into four substages: initial response, deformation accumulation and shear expansion, slip-surface coalescence and frontal advance, and low-velocity adjustment and stabilization. The maximum horizontal advance of the sliding front is 2.49 m, which exceeds the initial clearance of 0.60 m to the nearest house. Direct squeezing and burial risks are therefore indicated. The results provide a reference for risk identification, monitoring and early warning, and mitigation design of similar building-adjacent cut slopes.