渗流作用下某露天矿排土场边坡稳定性及敏感因素分析

Study on the slope stability and sensitive factors of an open-pit dump under seepage

以云南某露天矿内排土场为研究对象,运用Geo-Studio有限元数值模拟软件中的SEEP/W和SLOPE/W模块,对排土场边坡进行降雨入渗过程模拟及极限平衡分析,结果表明:当降雨强度为120 mm/d、连续降雨2 d后,边坡表面会出现暂态饱和区;当降雨强度为46 mm/d时,未出现暂态饱和区,降雨强度越大,暂态饱和区出现得越早;排土场边坡大量散体物质在降雨入渗作用下,其内部孔隙水压力和体积含水率会发生相应变化,导致边坡抗剪强度降低,进而引起排土场边坡失稳破坏。基于敏感性分析原理,利用SPSS进行正交试验,分析容重、内聚力、内摩擦角及降雨强度对边坡安全系数的影响程度,结果表明:各因素对边坡稳定性的敏感度排序为内摩擦角>土体容重>内聚力>降雨强度。

Taking an open pit dump in Yunnan as the object of study,using the SEEP/W and SLOPE/W modules in the finite element numerical simulation software Geo-Studio,the rainfall infiltration process and the limit balance ana-lysis of the dump slope were carried out.The results shown that when the rain lasted continuously for 2 days at an intensity of 120 mm/d,the transient saturation zone would present on the slope surface and be absent at an intensity of 46 mm/d,the greater the rainfall intensity,the earlier the transient saturation zone appeared.Under the action of rainfall infiltration into the slope containing bulk materials,the internal pore water pressure and bulk moisture changed accordingly,which lead to the decrease of slope shear strength and the failure of dump slope.On the basis of sensitivity analysis,the orthogonal test was carried out by using SPSS to see the influence of such factors as bulk density,cohesion,internal friction angle and rainfall intensity on slope stability.The results showed that the ranking of factors with sensitive to slope stability was internal friction angle,soil density,cohesion,rainfall intensity.