特厚高位顶板切顶自成巷围岩控制技术

Extra thick high roof cutting roof self⁃formed roadway surrounding rock control technology

为解决传统留煤柱沿空留巷煤炭采出率低、采掘接续紧张、煤柱应力集中、巷道支护难度大等棘手的难题,以响水煤矿播土区东二采区120313工作面为研究对象,通过短臂梁顶板围岩破坏机制力学模型受力分析与计算、FLAC3D数值模拟巷道顶板切顶卸压效果分析、现场实验的研究过程,确定巷道主动支护参数、顶板爆破参数、挡矸参数和临时支护参数,提出中厚煤层巷道特厚高位顶板“恒阻大变形锚索+巷道顶板双向定向预裂爆破+巷帮补强支护+可伸缩性U型钢挡矸+单体液压支柱临时支护”围岩稳定性控制技术。结果表明:根据顶板的力学性质,特厚高位顶板单根恒阻大变形锚索补偿支护力所需最大值为309 kN;回风巷道顶板切顶与未切顶比较,切顶时工作面超前支承压力最大值减小15%,巷道侧向支承压力最大值减小27%;巷道变形得到有效的控制,在滞后工作面160~175 m范围内巷道围岩趋于稳定。该工作面单位煤柱长度回收煤炭12.48 t,提高了区段煤炭采出率,降低了采矿成本。

In order to solve the problems such as low coal recovery rate,mining continuing tensely,coal column stress concentration,and difficulty of roadway support with the traditional coal retention pil⁃lar and gob⁃side entry retaining,East Second Mining 120313 working face of Xiangshui Coal Mine is taken as the research object,and the active support parameters,roof blasting parameters,stop bar pa⁃rameters and temporary support parameters are determined through the force analysis and calculation of the mechanical model of the surrounding rock failure mechanism of the short arm beam roof,and FLAC3D numerical simulation analysis of roadway roof cutting pressure relief effect,and the research process of field experiment.The stability control technology of surrounding rock of the extra thick upper roof of the roadway of medium thick coal seam that“constant resistance large deformation anchor cable+bidirectional presplitting blasting of roadway roof+roadway reinforcement support+flexible U⁃shaped steel stop bar+temporary support of single hydraulic pillar”is proposed.The results show that the maxi⁃mum value required to compensate the supporting force of a single constant resistance large deformation anchor cable of the extra thick upper roof plate is 309 kN according to the mechanical properties of the roof.Compared cut and uncut roof of return air roadway,the maximum value of the leading supporting pressure of the working face is reduced by 15%,and the maximum value of the lateral support pressure of the roadway is reduced by 27%in the case of cutting the top;the deformation of the roadway is effec⁃tively controlled,and the surrounding rock of the roadway tends to be stable within the range of 160-175 m after the lagging working face.The coal recovered is 13.44 ton per unit column length of the working face,which improves the coal recovery rate of the section and reduce the mining costs.