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基于沉陷预测的上下煤层协同开采工作面走向错距研究

Research on staggered distance of upper and lower coal seam cooperative mining face based on subsidence prediction

  • 摘要: 为研究层间距离较大、不属于近距离煤层范畴的上下煤层同采工作面的安全走向错距,以潞安集团伊田煤业2号煤层(上覆煤层)、11号煤层(下伏煤层)协同开采工作面为工程背景,基于下伏煤层采场顶板垮落特征及“竖三带”理论分析结果,提出下行协同开采条件下需要解决的科学问题为下伏煤层的开采活动不能影响上覆煤层的安全生产。建立了概率积分法开采沉陷计算模型,探究充分采动条件下,下伏11号煤层工作面开采对上覆2号煤层底板的沉陷影响范围。将下沉10 mm、倾斜3 mm/m、曲率0.08×10−3 /m和水平变形2 mm/m作为下伏煤层开采对上覆煤层的安全影响阈值,以上覆煤层工作面位于下伏煤层工作面开采沉陷影响范围之外为判据,并考虑1.5倍的安全系数,得出上下煤层同采工作面的合理走向错距为96.2 m。两工作面协同开采过程中,通过严格管控每班和每日的回采进度,使其前后错距始终大于96.2 m,监测上覆2号煤层工作面及其回采巷道的矿压显现情况,并与同类条件单层开采时的矿压规律进行对比分析。工程实践表明:2号煤层、11号煤层协同开采过程中,基于下伏11号煤层工作面充分采动条件下的开采沉陷范围,确定的上下煤层同采工作面走向错距合理可靠,上覆2号煤层工作面未受到下伏11号煤层工作面的开采沉陷影响,可以实现安全协同生产。

     

    Abstract: In order to study the safe staggered distance of the same mining face of the upper and lower coal seams, which does not belong to the category of contugous coal seams, taking the collaborative mining face of Yitian Coal Industry No. 2 Coal Seam (overlying coal seam) and No. 11 Coal Seam (underlying coal seam) of Lu'an Group as the engineering background, based on the roof collapse characteristics of the underlying coal seam stope and the theoretical analysis results of “three vertical zones”, the scientific problem to be solved under the condition of downward cooperative mining is that the mining activities of the underlying coal seam can not affect the safety production of the overlying coal seam. A probability-integrated mining subsidence prediction model was established to explore the influence range of mining in the underlying No. 11 coal seam working face on the subsidence of the overlying No. 2 coal seam floor under full mining conditions. The subsidence of 10 mm, inclination of 3 mm/m, curvature of 0.08×10−3 /m and horizontal deformation of 2 mm/m were taken as the safety impact threshold of the mining of the underlying coal seam on the overlying coal seam. The criterion is that the working face of the overlying coal seam is located outside the mining subsidence range of the working face of the lower coal seam. Considering the safety factor of 1.5 times, it is concluded that the reasonable strike dislocation distance of upper and lower coal seams is 96.2 m, the ground pressure appearance of the overlying 2# coal seam working face and its mining roadway is monitored, and the ground pressure law is compared and analyzed with that of single layer mining under the same conditions. Engineering practice shows that during the coordinated mining process of No. 2 coal seam and No. 11 coal seam, based on the mining subsidence range caused by the full mining conditions of the No. 11 coal seam, the determined staggered distance of the same mining face in the upper and lower coal seams is reasonable and reliable. The overlying No. 2 coal seam working face has not been affected by the mining subsidence of the lower No.11 coal seam, which can achieve safe collaborative production.

     

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