露井联采中采矿方法对露天边坡的稳定性分析研究

Influence of Mining Method on Stability of Open Pit Slope in the Open-underground Combined Mining Process

在露天矿露井联采阶段,地下开挖采矿方法的不合理选择可能会对露天边坡的稳定性造成扰动,以致出现边坡失稳、地面塌陷以及排土场滑塌等灾害事故,这就增加了对边坡以及排土场等的维护费用。为了减少地下开挖对边坡扰动的影响,结合某露天磷矿的工程背景,利用ANSYS有限元法进行数值模拟分析,通过对未开挖、上向水平分层充填法、空场法3种情况下对边坡和隔离带的影响分析,得出使用充填法进行地下开挖时,隔离层的变化较小,边坡局部有影响且可能发生破坏,则需对边坡加强防护措施。使用空场法时,开挖结束后采空区附近和隔离层底部的位移量比较大,在此种情况下边坡整体不会出现失稳,但局部可能发生破坏,需同时对边坡和隔离层做保护措施。通过对比可知充填法的整体安全系数较高,所以在今后的开采中可优先考虑充填法。

In the phase of open-underground combined mining,the unreasonable selection of underground mining methods may disturb the stability of open-pit slopes and even lead to such disasters occurrence as slope instability,surface collapse and dumping landslide. These increases the maintenance cost of open-pit slopes and dumps. In order to reduce the disturbance of underground excavation on slope,and combined with the engineering background of a certain open pit phosphate mine,the finite element method of ANSYS is used to carry out the numerical simulation analysis. Through the analysis of the influences on the slope and isolation zone under the three conditions of non-excavation,upward horizontal slicing filling method and open-pit method,it is concluded that the change of the isolation layer is small when using the filling method for underground excavation. Local slopes are affected and may be damaged, it is necessary to strengthen the protection measures for the slope. When the empty field method is used, the displacement near the goaf and the bottom of the isolation layer after the excavation is relatively large.In this case, the slope as a whole will not appear instability, but local damage may occur, The slope and isolation layer need to be protected at the same time. By comparison, it can be seen that the overall safety factor of the filling method is high, Therefore, filling method can be given priority in future mining.