丰山矿区充填开采过程的数值模拟研究

Numerical Simulation for Cut-and-Fill Mining Process of Fengshan Mining District

为了比较不同充填采矿方法对采场稳定性的影响,基于现场地质调查和室内试验得到的数据,采用有限单元法对-260 m--380 m范围内矿体开采和充填过程进行了数值分析,得到了每一施工步的应力场和屈服区分布规律。结果表明,联合采用胶结充填和尾砂充填可以有效控制采场围岩的稳定性。对于每一施工步而言,围岩中应力场和屈服区由于开挖效应先增大,后因充填作用又减小,该变化规律随施工步向前推进也同步前移。从整体上看,采场围岩应力和屈服区随施工步推进具有明显的趋势。充填体特别是胶结充填体有效地抑制了围岩应力释放和变形,减缓了岩层储备能量的释放速率,避免了出现冲击地压等动压现象。方案比选表明垂直矿体倾向开采方案最优。

To compare the effect of different cut-and-fill mining methods on the stope stability, numerical analysis was made, based on site investigation and in-door test, of the orebody mining and filling process in a 260 m - 380 m range by finite element method, from which the stress field and yield distribution law in every stage of construction was obtained. The results show that combined application of cemented fill and tailings fill can effectively control the stability of the stope wall rock. In each step of the construction, the stress field and yield area are first increased due to the excavation effect and then decreased due to the filling action, and this change synchronizes with the construction advance. On the whole, the stress field and yield area have a trend of becoming larger. The filling body especially the cemented one can effectively depress the release and deformation of the stress of wall rock, which relaxes the release rate of the stratum-preserved energy, thus a- voiding the occurrence of the dynamic pressure such as impact pressure. The scheme comparison shows that mining along the direction vertical to the orebody dip is the optimum.