Coal Engineering College, Shanxi Datong University

针对特厚煤层综放开采沿空掘巷时,留设宽煤柱护巷造成煤炭资源丢失严重,以及围岩变形量大、煤壁片帮等问题,以同忻煤矿8311工作面5311回风巷为工程背景,采用理论分析、数值模拟和现场观测相结合的方法,对其沿空掘巷护巷煤柱合理宽度的留设进行了分析。研究表明,理论分析得知留设煤柱宽度为6m左右时可确保5311回风巷位于沿空边缘煤体支承压力降低区和煤体应力屈服区,有利于巷道围岩的稳定。基于3DEC数值模拟分析,得到留设6m煤柱5311回风巷的稳定性以及8311工作面回采后沿空掘巷超前段顶板、实体煤帮、煤柱内围岩应力分布和塑性区演化特征。经现场应用,验证了综放开采留设窄煤柱掘巷技术的优越性和可靠性。

and coal wall fragmentation caused by the reserve of wide coal pillars to protect the goaf during fully mechanized top coal ca-ving in extremely thick coal seams, taking the 5311 air return roadway of the 8311 working face in Tongxin Coal Mine as theengineering background, a study was conducted on the selection of the reasonable width of the coal pillar for protecting theroadway along the goaf by combining theoretical analysis, numerical simulation, and on-site observation. Research has shownthat theoretical analysis indicates that when the width of the reserved coal pillar is about 6 meters, it can ensure that the5311 air return roadway is located in the area where the support pressure of the coal body decreases and the stress yield areaof the coal body along the goaf edge, which is conducive to the stability of the surrounding rock of the roadway. Based on3DEC numerical simulation verification, the stability of the 5311 air return roadway with a 6 m coal pillar and the evolutioncharacteristics of the stress distribution and plastic zone in the overlying roof, solid coal slope, and surrounding rock insidethe coal pillar of the 8311 working face after mining along the goaf are studied. The on-site application results also prove thesuperiority and reliability of the narrow coal pillar excavation technology in fully mechanized top coal caving mining.