煤层群接续开采方案优选评价研究

Study on optimization and evaluation of continuous mining scheme in coal seam group

为优选榆树岭矿煤层群接续开采方案,利用FLAC3D模拟研究了下行开采和上行开采2种煤层群接续开采方案下煤层完整性和工作面应力分布规律,并比较了2种方案的经济效益。结果表明:上行开采时煤层受到一定程度的塑性破坏,但通过对下_(7)、下_(8)煤层工作面运输巷、回风巷与下_(10)煤层工作面运输巷、回风巷内错10 m布置,可有效减小煤层塑性区破坏范围,下_(7)、下_(8)煤层工作面未破坏区占比分别为87.5%,60.4%,煤层完整性满足安全回采要求;相较于下行开采,上行开采时下_(7)、下_(8)煤层工作面平均应力分别降低了45.3%,34.9%,下_(7)、下_(8)煤层工作面最大支承应力分别降低了66.7%,36.4%,且矿井经济效益提高了64.9%。因此优选上行开采作为榆树岭矿煤层群接续开采方案。采用层次分析法和模糊数学理论对煤层群接续开采方案优选结果进行了理论验证:通过建立煤层群接续开采方案综合评价指标模型,构造准则层相对于目标层与指标层的判断矩阵并进行一致性检验,得到评价指标权重向量;采用线性函数法和二元对比排序法构造了指标层各因素相对于下行开采和上行开采的隶属度矩阵,求得综合隶属度指标矩阵;根据评价指标权重向量和综合隶属度指标矩阵,得到下行开采、上行开采方案的综合评价权重分别为0.17087,0.70442,验证了上行开采作为该矿煤层群接续开采最优方案的可行性。

In order to optimize the continuous mining scheme of coal seam group in Yushuling Coal Mine,FLAC3D simulation is used to study the coal seam integrity and working face stress distribution law under two continuous mining schemes of downward mining and upward mining of coal seam group, and the economic benefits of the two schemes are compared. The results show that the coal seam suffers plastic damage to a certain extent during upward mining, but the damage scope of the coal seam plastic zone can be effectively reduced by arranging the transportation roadway and return air roadway of the lower No.7 and No.8 coal seams and the transportation roadway and return air roadway of the lower No.10 coal seam in an inboard way of 10 m. The undamaged areas of the lower No.7 and No.8 coal seams account for 87.5% and 60.4% respectively, and the integrity of the coal seam meets the requirements of safe mining. Compared with the downward mining, the average stress of the lower No.7 and No.8 coal seams during upward mining is reduced by 45.3% and 34.9%respectively, and the maximum supporting stress of the lower No.7 and No.8 coal seams is reduced by 66.7% and 36.4% respectively, and the economic benefit increase by 64.9%. Therefore, the upward mining is preferred as the continuous mining scheme of coal seam group in Yushuling Coal Mine. The optimization result of continuous mining scheme of coal seam group is theoretically verified by using analytic hierarchy process and fuzzy mathematics theory. By establishing the comprehensive evaluation index model of the coal seam group continuous mining scheme, constructing the judgment matrix of the criterion layer relative to the target layer and the index layer and carrying out the consistency test, the evaluation index weight vector is obtained. The membership degree matrix of each factor of the index layer relative to the downward mining and upward mining is constructed by using the linear function method and the binary comparison and ranking method, and the comprehensive membership degree index matrix is obtained. According to the evaluation index weight vector and the comprehensive membership index matrix, the comprehensive evaluation weights of the downward mining and upward mining schemes are obtained as 0.170 87 and 0.704 42 respectively, which verifies the feasibility of upward mining as the optimal scheme for the continuous mining of the coal seam group in this mine.