降雨条件下含缓倾软弱夹层矿山高边坡稳定性分析

Stability Analysis of High Slope with Gently Inclined Weak Interlayer under Rainfall Condition in Mine

降雨是诱发边坡失稳的重要因素之一,为探究降雨对含缓倾软弱夹层矿山高边坡稳定性的影响,结合工程实际,基于饱和-非饱和渗流理论,模拟了不同降雨工况下矿山边坡的渗流过程,并运用强度折减法对降雨作用下边坡的稳定性进行了计算。结果表明:软弱夹层会阻碍降雨渗流通道,导致孔压曲线发生畸变;边坡竖直截面上的孔压增长率自上而下呈减小趋势,在相同时间段内浸润深度与坡面孔压的增量逐步减少;降雨过程中边坡主要沿软弱夹层发生塑性变形,降雨6 h后坡面的整体位移会发生突变;4种工况下坡中位置位移的变化量最大,暴雨工况下坡脚处的位移相较于其他工况会发生陡增;暴雨工况降雨24 h后边坡的稳定性系数达到最低,且小于技术规范的要求,边坡处于危险状态。研究结果可为类似地质条件下边坡稳定性的预测、防护与评价提供参考。

Rainfall is one of the important factors inducing slope instability.In order to explore the influence of rainfall on the stability of high slope with gently inclined weak interlayer in mine,combined with engineering practice,based on saturated-unsaturated seepage theory,the seepage process of mine slope under different rainfall conditions was simulated,and the slope stability under rainfall was calculated by strength reduction method.The results show that the weak interlayer will hinder the rainfall seepage channel and cause the distortion of pore pressure curve.The increase rate of pore pressure on the vertical section of the slope decreases from top to bottom,and the increment of infiltration depth and pore pressure on the slope gradually decreases in the same period.The plastic deformation of the slope mainly occurs along the weak interlayer during rainfall,and the overall displacement of the slope has a mutation in 6 hours of rainfall.The displacement variation of the middle position of the slope under the four conditions is the largest,and the displacement at the foot of the slope under the rainstorm condition will increase sharply compared with other conditions.The stability coefficient of the slope reaches the minimum in 24 hours of rainfall under rainstorm conditions,which is less than the requirements of technical specifications,and the slope is in a dangerous state.The research results provide a certain reference for the prediction,protection and evaluation of slope stability under similar geological conditions.