强降雨常触发大规模滑坡灾害，对人民生命财产构成严重威胁。研究滑坡的成因机制及强降雨条件下雨水的渗透规律，对于滑坡监测预警和防治至关重要。以游家河滑坡为例，通过多年宏观巡查资料及全自动监测数据，揭示游家河滑坡次级滑体的变形机理，并阐述降雨导致的裂隙渗透过程。借助Geostudio软件进行模拟分析，进一步探讨不同降雨强度对次级滑体演化特征的影响。研究表明：强降雨是触发次级滑体阶跃式变形的主要因素。4次阶跃变形前均有显著强降雨发生，且变形响应通常滞后于降雨1 ~ 2 d。游家河滑坡属浅层滑坡，其平缓层坡度较缓，利于降雨在坡面径流与渗透过程中在平缓层堆积，形成特殊的“孔隙+裂隙”复合入渗模式。坡体结构、降雨强度以及挡土墙的存在共同调控着降雨的补给过程，进而影响滑坡的稳定性。数值模拟揭示，降雨首先渗透进入坡体的平缓区域，而挡土墙不仅阻碍了坡脚处的雨水排放，还对坡体位移起到了限制作用。随着降雨强度的增大，次级滑体的稳定性逐渐减弱。本次研究结果为滑坡的监测预警系统及防治措施提供参考。

Large-scale landslide disasters are frequently triggered by heavy rainfall, posing significant threats to human life and property. The study of landslide formation mechanisms and rainwater infiltration patterns under heavy rainfall conditions is considered crucial for landslide monitoring, early warning, and prevention. The Youjiahe landslide was used as a case study to elucidate the deformation mechanism of the secondary sliding body. Years of macro-inspection data and fully automated monitoring data were analyzed. The fissure infiltration process induced by rainfall was elaborated. Geostudio software was employed for simulation analysis. The impact of varying rainfall intensities on the evolution characteristics of the secondary sliding body was further examined. The results show as follows. Heavy rainfall is identified as the primary factor triggering step-like deformations in secondary sliding bodies. Significant rainfall events are observed prior to each of four step-like deformation occurrences. Deformation responses generally exhibit a 1 ~ 2 day temporal lag relative to rainfall events. The Youjiahe landslide is characterized as a shallow landslide with gently sloping flat layers. Rainfall accumulation on slope surfaces is facilitated during runoff and infiltration processes. A unique "pore + fissure" composite infiltration mode is formed by this slope structure. The rainfall recharge process is jointly regulated by slope structure, rainfall intensity, and retaining wall presence. Landslide stability is consequently influenced through these regulatory mechanisms. Rainfall infiltration is initially observed in flat slope areas through numerical simulations. Rainwater discharge at the slope toe is impeded by retaining walls. Slope body displacement is simultaneously restricted by these retaining structures. The stability of secondary sliding body is progressively diminished with increasing rainfall intensity. The research findings are provided as references for landslide monitoring and early warning systems and preventive measures.