Study on overburden migration and breaking law of ultra-wide working face in deep mining
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 ex-tended 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 com-posite 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 work-ing 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.
water-conducting fracture zoneoverburden fractureoverburden migration and fracturefully-mechanized mining
万方数据
维普
