基于开拓巷道稳定性分析的泥河铁矿阶段开采顺序研究

Research on Stepwise Mining Sequence of Nihe Iron Mine Based on the Stability Analysis of Opening Roadways

埋深超过600 m的泥河铁矿一期工程设计为两阶段(-750 m阶段、-830 m阶段)充填开采,开拓巷道的稳定性是影响阶段开采顺序选择的关键因素之一。选取典型勘探线剖面建立二维有限元计算模型,根据一期工程可能的阶段开采顺序制定自下而上(方案一)和自上而下(方案二)2种计算方案。对2种方案各开采步骤进行有限元应力分析,对比2种方案下开拓巷道的围岩应力分布状态和巷道稳定的安全系数,选取合理的阶段开采顺序。结果表明,在开采过程中2种阶段开采顺序下的绝大部分巷道围岩局部有拉应力产生;方案二与方案一相比,拉应力的分布范围更小,开拓巷道围岩最小主应力最小值较大,安全系数也较高,开拓巷道更为稳定。因此,采用自上而下开采顺序的方案二即先采-750 m阶段、后采-830 m阶段的开采方案更优。

Nihe Iron Mine with burial depth of over 600 m is designed to be exploited by two-stage（- 750 m lever,- 830 m lever） backfill mining method in its first phase project. The stability of opening roadways is one of the key factors that affect the selection of stepwise mining sequence. The typical exploration profiles are chosen to establish two-dimensional finite element calculation models. Two calculation schemes which are the bottom-up stage mining sequence（ scheme one） and the topdown stage mining sequence（ scheme two） are formulated according to the possible stepwise mining sequences. Finite element stress analysis is conducted at different mining steps of the two schemes. The surrounding rock stress distribution of the opening roadways and safety factors of roadway stability are contrasted in the two schemes to select the reasonable stage mining sequence. The results show that tensile stress occurs in the fractional rock-mass around the majority of opening roadways during exploitation in the two mining sequences. Compared with scheme one,tensile stress distribution region in scheme two is smaller,and minimums of minor principal stress in the surrounding rock of opening roadways are larger,with higher safety factors and more stable opening roadways. Therefore,scheme two which adopts the top-down stage mining sequence,namely mining-750 m level first and- 830 m level later,is optimal.