深部矿体开采对隔离矿柱及回填体的稳定性影响研

根据某矿山开采实际, 利用PFC^2D建立了崩落法和充填法开采深部矿体的数值模型, 分析了2种方法回采深部矿体对上部隔离矿柱及回填体稳定性的影响。结果表明, 崩落法回采时, 上部隔离矿柱发生了破坏, 上盘地表出现拉应力集中, 塌陷区回填体和围岩发生较大沉降;隔离矿柱破坏前, 回填体和围岩的应力和位移变化不大;隔离矿柱破坏后, 上下盘地表的水平拉应力随开采深度增加逐渐增大, 且隔离矿柱的水平应力发生显著跌落。充填法回采时, 隔离矿柱未出现整体破坏, 上下盘地表未出现明显塌陷, 上下盘地表和回填体的水平应力变化不大, 但塌陷废石和隔离矿柱的水平应力随矿体开采深度增加而增加。研究结果可为矿山塌陷区和采空区治理以及深部资源安全开采提供科学依据。

Influence of Deep Ore-Body Mining on Stability of Barrier Pillars and Backfill

According to the mining practice in a mine, a numerical simulation model of deep ore-body mining by block caving and cut-and-fill   was established with PFC2D, and the influence of two methods on the stability of the top barrier pillars and backfill was systematically analyzed. Results show that the caving mining causes the failure of the top barrier pillars, leading to the tensile stress concentrated on the ground surface of the hanging wall and great subsidence of the backfill and surrounding wall in the subsided area. Before the failure of the barrier pillars, there is little change in the stress and displacement of the backfill and surrounding wall. However, after the barrier pillar is destroyed, the horizontal tensile stress acting on the surface of the hanging wall and footwall gradually increases as the mining goes deeper, and the horizontal stress acting to the barrier pillars drops significantly. It is found that during the  cut-and-fill mining, the barrier pillar is not completedly destroyed, and there's neither obvious collapse of the hanging wall and footwall nor great variation in the horizontal stress acting on the hanging wall and footwall and the backfill. However, the horizontal stress of the collapsed waste rock and barrier pillars increases as the mining goes deeper. This research results can provide scientific basis for the control of subsided area and mined-out area in the mine, as well as for the safe exploitation of mineral resources in the deeper earth.