井工采区不同开采时序对边坡滑移破坏机制的影响

以紫金山金铜矿开采为工程背景,根据矿山规划设计,露采至+100 m水平后进行井工开采。为了研究井工开采对露天边坡的影响,采用FLAC3D建立数值模型,研究采区位于边坡体不同空间位置对边坡稳定性产生的不同作用机制,分析露天边坡和采空区围岩位移演化规律、应力分布规律。数值模拟结果表明:当井采区位于边坡坡脚区时,井工开采直接破坏了坡脚区边坡岩体,坡面整体向坡脚处滑移,最大水平位移达到2.21 m,最大竖向位移达到1.67 m;当井采区位于坡中区开采时,其开采破坏了坡中边坡岩体,可能导致上部坡体失稳破坏;当井采区位于坡外区时,由于采区上部岩层沉陷导致边坡整体坡角减小,从而有利于边坡整体稳定性。对比3种开采位置,采区位于坡脚时对边坡稳定性最不利,采区处于坡外时采动效应对边坡稳定性的影响最低。

Influence of Different Mining Timings on Side Slope Slip Failure Mechanism in Well Working Area

Taking Zijinshan gold and copper mining as the engineering background,according to the mine planning and design,underground mining starts after open pit mining reaching the+100m level.In order to study the influence of underground mining on open-pit slope,FLAC3D is used to establish a numerical model to study the different action mechanism of different spatial positions of mining area on slope stability,and analyze the displacement evolution law and stress distribution law of surrounding rock of open-pit slope and goaf.The numerical simulation results show that when the well mining area is located at the foot of the slope,the well mining directly destroys the slope rock mass at the foot of the slope,and the slope slides to the foot of the slope as a whole.The maximum horizontal displacement is 2.21 m and the maximum vertical displacement is 1.67 m.When the well mining area is located in the middle of the slope,its mining destroys the rock mass of the middle slope,which may lead to the instability and failure of the upper slope.When the well mining area is located outside the slope,the overall slope angle of the slope is reduced due to the subsidence of the upper strata of the mining area,which is conducive to the overall stability of the slope.Comparing the three mining positions,the mining area at the foot of the slope is the most unfavorable to the slope stability,and the mining effect has the lowest impact on the slope stability when the mining area is outside the slope.