地下采深变化的露天矿残余边坡稳定性分析

为防止露天转地下开采中,露天矿残余边坡突然垮落可能引发安全事故,以孟家铁矿露天转地下开采工程为研究背景,采用FLAC3D数值模拟方法,研究了随着地下开采深度不断增加,露天矿残余边坡围岩的应力场、位移场及塑性区的变化规律,以及覆盖岩层对边坡稳定性的影响。结果表明:(1)覆盖层散体能够吸收和转移露天矿残余边坡的应力,对能量释放起到缓冲作用,进而起到支撑边坡及围岩的作用;(2)随着地下开采深度不断增加,始终保持覆盖岩层上平面处于一个稳定的标高,能够有效改善露天矿边坡应力场和塑性区的分布状态,对边坡围岩变形起到一定的抑制和约束作用。

Stability Analysis of Residual Slope of Open-pit Mine with Variation of Underground Mining Depth

In order to prevent the safety accident caused by the sudden collapse of the residual slope in a transition from open-pit to underground mining， based on the background of the research on the transition from open-pit to underground mining project of Mengjia Iron Mine， the variation law of the stress field， the displacement field and the plastic zone distribution in the surrounding rock of the residual slope of open-pit， and the influence of the overlying rock layer on slope stability， with the increasing of underground mining depth， are studied by using FLAC3D numerical simulation method. The results show that: ①the overlying rock layer can absorb and transfer the stress of the residual slope in opencast mine， which can buffer the energy release and then support the slope and surrounding rock； ②with the increasing of the underground mining depth， keeping the plane of overlying rock layer at a stable elevation can effectively improve the stress field and plastic zone distribution in open-pit slope， and restrain and constrain the deformation of surrounding rock of slope to a certain extent.