胶结充填体拱效应作用下的水平矿柱回采安全厚度研究

Thickness of Horizontal Pillar for Safe Extraction Under Arching Effect of Cemented Backfill

通过建立三维胶结充填体拱应力模型,得到胶结充填体竖向荷载计算公式,并根据四边固支顶板模型和岩体极限抗拉强度准则,得到了水平矿柱回采安全厚度确定方法。在某铅锌矿612采场水平矿柱回采的运用实践表明,解析模型计算的胶结充填体竖向应力与数值模拟结果基本吻合,数值模拟中顶板未出现塑性区,验证了计算确定的保留顶板厚度满足安全生产需求;回采过程监测结果表明,监测点附近的最大累计位移低于极限位移,保留顶板趋于稳定,确定的水平矿柱回采安全厚度具有足够的可靠性。

Based on an established three-dimensional analytical model for arching stress of cemented backfill,a calculation formula for vertical load of cemented backfill was obtained.According to a model of four-sided fixed roof and a criterion for ultimate tensile strength of rock mass,a method to determine the thickness of horizontal pillar for safe extraction was obtained.The application practice of horizontal pillar extraction in 612 stope of a lead-zinc mine shows that the vertical stress of cemented backfill calculated with this analytical model is basically consistent with the numerical simulation results,and no plastic zone occurs in the roof in numerical simulation,which verifies that the reserved roof thickness determined by calculation meets the requirement of safe production.The results of stoping process show that the maximum cumulative displacement near the monitoring point is lower than the displacement limit,and the reserved roof tends to be stable.It is concluded that the determined thickness of horizontal pillar is reliable for safe extraction.