破碎围岩条件下预留矿柱开采对充填体稳定性的影响

Influence of Mining Reserved Pillar on Backfill Body Stability in Broken Rocks

为研究预留矿柱开采对其上部充填体稳定性的影响，结合某金矿矿岩赋存条件，采用考虑封闭系数的矿柱开采经验公式，提出开采尺寸为180m×15m×20m（走向长度×高度×宽度）的矿柱开采方案。利用MAP3D软件对590～605m水平间矿柱开采进行数值分析，结果表明：在一般原岩应力情况下，矿柱完全开采后上部充填体仍保持稳定；在较差原岩应力情况下，矿柱完全开采后上部充填体受压作用明显，可能发生失稳破坏。应用极限平衡方程对矿柱开采经验公式进行修正，提出通过减小采场跨度及加强支护的方式，降低对充填体单轴抗压强度的要求，能保证预留矿柱的安全回采和上部充填体的稳定。研究结果可为其他类似矿山提供设计思路。

To study the influence of mining reserved pillar on backfill body stability,a mining size scheme of 180 m×15 re×20 m （ strike length x height xwidth） for ore pillars is proposed by using a pillar design method by considering confinement factor and combining ore rock occurrence conditions in one gold mine. The mining of pillar between 590 and 605 mRL is nu- merically analyzed by using MAP3D software. The results indicate that the upper backfill body still keeps stable when the pillar is mined out in normal primary rock stress ,and in worse primary rock stress ,large portion of the upper backfill body is predic- ted to be in tension which means it may occur unstable failure. The empirical pillar design formula is modified by using limit e- quilibrium equation and the requirement of reducing the backfill body＇s uniaxial compressive strength by reducing the stope span and strengthening supporting is put forward. This research conclusion can ensure the safety of mining out the reserved pil- lar and the stability of the upper backfill body. It also can provide design ideas for other similar mines.