深部开采超宽工作面覆岩运移破断规律研究

Study on overburden migration and breaking law of ultra-wide working face in deep mining

以高家堡煤矿4号煤层赋存条件为背景,采用理论分析、数值模型模拟相结合的方法,对4号煤上覆岩层中关键层位置进行了判别,明确了加长工作面的来压步距,研究了工作面长度分别为120、140、150、180、200、260 m条件下的覆岩运移特征。结果表明:工作面上覆岩层中包含6层关键层,且距4号煤上108 m处的复合岩层为主关键层,基本顶为包含粗粒砂岩、泥岩、中粒砂岩和粉砂岩在内的复合岩层1且为亚关键层,当工作面进行开采后,关键层以下所有亚关键层均发生破断。理论计算与数值模拟所得的工作面初次来压步距均在为50 m左右,周期来压步距均在20~25 m,与实际情况相符合。不同工作面长度的覆岩运移分布状态基本相同,且随着工作面长度的增加,采空区中部位移变化量最大,由7.72 m增加到7.81 m,而工作面两端覆岩运移量变化并不明显。研究结果可为工作面安全高效回采、矿井接续工作面面长设计布置提供有效借鉴,具有重要的现实生产指导意义。

Based on the occurrence conditions of No.4 coal seam in Gaojiapu Coal Mine,the location of key strata in the overlying strata of No.4 coal seam was identified by combining theoretical analysis and numerical model simulation.The weighting interval of the extended working face was defined,and the overburden migration characteristics under the conditions of working face length of 120,140,150,180,200 and 260 m were studied.The results show that there are 6 key layers in the overburden of the working face,and the composite rock layer at 108 m above the No.4 coal is the main key layer.The basic roof is the composite rock layer 1 including coarse-grained sandstone,mudstone,medium-grained sandstone and siltstone,which is the sub-key layer.When the working face is mined,all sub-key layers below the key layer are broken.The initial weighting interval of the working face obtained by theoretical calculation and numerical simulation was about 50 m,and the periodic weighting interval was 20-25 m,which was consistent with the actual situation.The distribution state of overburden migration with different working face lengths was basically the same,and with the increase of working face length,the displacement change in the middle of goaf was the largest,from 7.72 m to 7.81 m,while the change of overburden migration at both ends of working face was not obvious.The experimental results provide an effective reference for the safe and efficient mining of the working face and the design and layout of the working face length of the mine,which has important practical production guiding significance.