大直径深孔空场嗣后充填法采场结构参数优化及稳定性分析

Optimization and Stability Analysis of Stope Structure Parameters of Large-diameter Deep Hole Open Stoping with Subsequent Filling

大直径深孔空场嗣后充填法是安全高效开采倾斜极厚矿体的有效方法,合理的采场结构参数是维持采场稳定的前提。以Jama铜矿1000万t/a超大规模地下开采为工程背景,利用Mathews稳定图法计算了采场稳定区间和水力半径,并基于“隔三采一”的开采方案,采用FLAC^(3D)软件开展了4组采场结构参数条件下的采场稳定性数值模拟,从而优选出合理的高中段大采场结构参数。Mathews稳定图法采场顶板、侧帮暴露尺寸与水力半径的关系分析表明,当采场顶板跨度为15 m、中段高度为100 m时,采场长度应小于46 m。数值模拟结果表明:二步骤矿柱宽度从15 m增加至19.5 m时,采场顶板的位移、塑性区体积随着跨度增大而增加,底部结构堑沟的两帮安全系数较低且易发生部分剪切破坏。数值模拟与Mathews稳定图法分析结果一致,确定了大直径深孔空场嗣后充填法的最优采场结构参数为采场长度45 m,一步骤矿房宽15 m,二步骤矿柱宽18 m,采场高100 m。研究结果为实现倾斜极厚矿体高中段大采场安全回采提供了理论支撑。

Large-diameter deep hole open stoping with subsequent filling is a safe and efficient mining approach to utilize inclined and extremely thick orebody.Reasonable stope structure parameters is key premise to stope stability.Aiming at massive underground mining with a capacity of 10 Mt/a at Jama Copper Mine,stable zone and hydraulic radius are calculated using Mathews stability graph,and stope stability is numerically simulated using FLAC^(3D) software to optimize the stope structural parameters with high section and large stope.Numerical simulation is operated with respect to four parameter combinations in the mining pattern of"mining one at three stope intervals".The relationship of exposed areas of stope roof,sidewall and hydraulic radius is revealed by Mathews stability graph.Results shows that stope roof span is favorable at 15 m,stope length is limited to 46 m when stope height is 100 m.When the span of secondary stope increases from 15 m to 19.5 m,the roof displacement and plastic zone volume of stope are accordingly increased.Sidewalls of trench at bottom structure have a relatively low safety factor and therefore tend to suffer a range of shear failure.Since the numerical simulation results are consistent with the evaluation of Mathews stability graph,the stope structure parameters are optimized as 45 m in stope length,15 m in the preliminary stope width,18 m in the secondary stope width,and 100 m in stope height.The research results provide theoretical support for the safety mining of the high and middle sections of the inclined extremely thick orebody.