为了研究降雨作用对花岗岩残积土边坡稳定性的影响，进行了3种降雨强度（30、60、90 mm/h）、2种降雨时长（3、12 h）下的室内模型箱试验，监测了湿润锋、竖向位移等变化规律，使用PFC离散元软件对花岗岩残积土直剪试验进行模拟，标定不同含水率下花岗岩残积土的细观参数，并以此参数建立离散元边坡模型试验模型，分析位移场、转动场、失稳指标、力链、组构各向异性等细观变形和力学机制，揭示模型箱试验中边坡失稳的细观机制。结果表明：当降雨强度达到60 mm/h或以上时，边坡的滑移和扰动范围大幅扩大，滑移体沿着临坡面呈现圆弧形；边坡滑移损失率随降雨时间呈现先减小后增加的趋势，短时间的低强度降雨可以加固边坡，但持续降雨会导致滑移损失率显著上升；边坡中土体颗粒的位移和旋转角在9 h后显著增加，形成明显的圆弧形滑移破坏面；在降雨时长达到9 h后，边坡内力链分布和接触力各向异性显著变化，边坡的滑移面上的力链断裂，稳定区域内力链密集。To investigate theimpact of rainfall on the stability of granite residual soil slopes

indoormodel box tests were conducted at three rainfall intensities (30

60

90 mm/h)and two rainfall durations (3

12 h). The variations in wetting front andvertical displacement were monitored. PFC discrete element software was used tosimulate direct shear tests of granite residual soil

calibrate the mesoscopicparameters of granite residual soil for varying moisture contents

and developa discrete element slope model. The analysis concentrated on the displacement androtation fields

instability indicators

force chains

and fabric anisotropy toreveal the mesoscopic deformation and mechanical mechanisms underlying slopeinstability in the model box tests. The results show that when the rainfallintensity reaches 60 mm/h or above

the slip and disturbance range of the slopeexpand significantly

and the slip body exhibits a circular arc shape along theslope face. The slip loss rate of the slope initially decreases and thenincreases with prolonged rainfall; short-term low-intensity rainfall can stabilizethe slope

but continuous rainfall significantly increases the slip loss rate.After 9 hours of rainfall

the displacement and rotation angle of soilparticles in the slope increase markedly

forming a distinct circular arc slipfailure surface. Furthermore

after 9 hours of rainfall

the distributions of forcechains and contact force anisotropy within the slope change significantly

withforce chains on the slip surface breaking and densely concentrating in stableregions.