原位煤柱沿空留巷围岩控制机理及工程应用

Surrounding rock control mechanism and engineering application of in-situ coal pillar in gob-side entry retaining

针对传统沿空留巷技术中施工工艺复杂,机械化程度低,支护体与围岩在刚度、强度和结构上不耦合的问题,提出了原位煤柱沿空留巷围岩控制技术,分析了一次采动作用下原位煤柱侧向支承压力的动态演化过程,建立了"限定变形"原位煤柱力学模型,计算出了原位煤柱的合理宽度,提出了结构协同的支护原理,确定了锚梁网索作为基本支护和π型钢梁+单体支柱作为加强支护的协同围岩控制技术。工程实践表明,原位煤柱侧低位基本顶断裂、回转、触矸运动稳定后,原位煤柱对基本顶断裂的岩块起到较好的承载作用,降低了沿空巷道围岩的支护难度,该技术已在段王集团友众煤矿30104工作面一次采动作用下成功应用。

There are some defects existing in the traditional gob-side entry retaining technology, such as the complexity of the construction technology, the low degree of mechanization, and non-coupling states for the stiffness, strength and structure of the support system and surrounding rock. In view of the above-mentioned defects, the surrounding rock control technology using in-situ coal pillar in gob side retaining roadway is proposed. The dynamic evolution process of lateral abutment pressure on the in-situ coal pillar under the influence of primary mining is analyzed. The "limited deformation" mechanical model of in-situ coal pillar is established. The reasonable width range of in-situ coal pillar is calculated. The supporting principle of structural synergy is put forward. This work proposes the synergetic support technology in which the wire meshes beam and cable anchor are used as the basic support mode while the π type steel beam and single prop are used as the strengthening support mode. The engineering practice demonstrates that after the movement(including the fracture, rotation and touching gangue) of the main roof next to the low side of the in-situ coal pillar, the in-situ coal pillar plays a good role as the load bearing subject under the broken rock from the main roof. This reduces the supporting difficulty of surrounding rock of the gob-side entry. The technology has been successfully applied in the 30104 working face of Youzhong coal mine.