降雨入渗对含缓倾软弱夹层矿山边坡的稳定性影响机制研究

Study on the Influence Mechanism of Rainfall Infiltration on the Stability of Weak Interlayer Mine Slope

含缓倾软弱夹层的矿山边坡在连续降雨后易发生滑坡,以四川峨眉黄山石灰石矿山磨环凼西侧新滑坡为例,通过现场勘查、工程地质条件分析,利用极限平衡法对该滑坡进行稳定性分析,并建立含软弱夹层无限边坡计算模型分析降雨入渗对此类矿山边坡稳定性的影响机制。结果表明:降雨入渗引起的边坡内部滑动面孔隙水压力上升是诱发滑坡的主要原因;软弱夹层的不透水性会引起滑动面孔隙水压力突变,导致边坡稳定性骤减;降雨入渗的速率、雨水入渗的时长、边坡岩体的含水状态及软弱夹层的不透水特性决定了在降雨入渗的整个过程中滑动面孔隙水压力对边坡稳定性的影响程度大小。

Mine slopes with gently dipping soft interlayers are often prone to landslides after rainfall.Taking the new landslide on the west side of Mohuandang at Huangshan limestone mine in Sichuan Emei as an example,through on-site investigation and analysis of engineering geological conditions,the limit equilibrium method is used to solve the problem.The stability of the landslide is analyzed,and an infinite slope model with weak interlayers is established to analyze the influence mechanism of rainfall infiltration on the stability of such mine slopes.The results show that the increase in pore water pressure on the sliding surface of the slope caused by rainfall infiltration is the main cause of landslides;the impermeability of the soft interlayer will cause sudden changes in the pore pressure of the sliding surface,leading to a sudden decrease in slope stability;earthquakes in mines disturbance will not directly induce landslides,but will aggravate the occurrence of landslides when coupled with rainfall;the rate of rainfall infiltration,the duration of rainwater infiltration,the water content of the slope rock mass,and the impermeable characteristics of weak interlayers determine the impact of rainfall infiltration.The sensitivity of the slope stability at each stage of infiltration to the pore water pressure of the sliding surface.