万磊

摘 要：本文以新集二矿211112工作面地质条件为背景，运用FLAC 3D数值模拟方法，分析研究大倾角松软煤层大面积空顶区顶板和煤壁稳定性。研究表明：在片帮深度达到6 m后，应力释放降低幅度减小，应力释放最大区域扩大，顶板冒顶发生的可能性较大;随着片帮深度增加，在空顶区上部应力释放区域逐渐扩展的同时，剪切应力释放向上方岩层发展，顶板稳定性随之降低;超前支承压力峰值先增加后减小，存在片帮现象时超前支承压力峰值位置向深部转移，在超前支承压力峰值点后，垂直应力值随着片帮深度的增加而增大，增幅逐渐下降;随着空顶区的形成，工作面超前支承压力重新分布，在空顶区前方煤壁中重新形成应力集中，继续产生片帮的危险性稍有降低。通过数值模拟的分析研究，为现场实际对工作面片帮冒顶原因和处理方法提供理论依据。

关键词：FLAC 3D;大倾角煤层;数值模拟;顶板

中图分类号：TD353     文献标识码：A       文章编号：1003-5168（2021）30-0061-04

Abstract： Based on the geological conditions of 211112 working face in Xinji No.2 coal Mine， FLAC 3D numerical simulation method is used to analyze and study the stability of roof and coal wall of large area empty roof area in large inclined soft coal seam. The results show that when the spalling depth reaches 6 m， the reduction range of stress release decreases. The maximum area of stress release expands， and the roof fall is more likely to occur. With the increase of spalling depth， the stress release area in the upper part of the empty roof area gradually expands， meanwhile the shear stress release develops to the upper strata， and the roof stability decreases. The peak point of the leading abutment pressure increases first and then decreases. When there is spalling phenomenon， the peak position of the leading abutment pressure shifts to the deep. After the peak point of the leading abutment pressure， the vertical stress increases with the increase of the spalling depth， and the increase rate decreases gradually. With the formation of the empty roof area， the advance abutment pressure of the working face is redistributed. The stress concentration is reformed in the coal wall in front of the empty roof area， and the risk of continuous spalling is slightly reduced. Through the analysis and research of numerical simulation， it provides a theoretical basis for the cause and treatment of spalling roof fall in working face.

Keywords： FLAC 3D; high angle coal seam; numerical simulation; roof

近年來，随着我国矿井开采强度的不断加大，为了保证矿井开采的可持续性，一些赋存条件相对复杂的大倾角或急倾斜煤层的开采也正在被考虑[1-4]。我国西部地区大量赋存煤层的倾角都在35°以上，随着开采强度和深度的不断增大，大倾角煤层已经成为许多矿井的主采煤层。然而在实际生产中，由于各矿井大倾角煤层的赋存条件差异性大，存在倾角大、围岩运动复杂、支架设备稳定性差、煤壁稳定控制困难、底板滑移机理不明确、工作面安撤时间长、工作面安全防护差等困难，实际开采中仍面临许多技术问题[5-10]。……