沿空留巷围岩受力变形特征及支护对策

Mechanical and deformation characteristics of gob-side entry retaining surrounding rock and support methods

以贺西煤矿3311工作面沿空留巷为背景,采用FLAC^(3D)有限差分程序计算分析了不同工作面回采阶段沿空留巷围岩、充填墙体及煤柱中的应力、变形分布特征,提出了沿空留巷合理的支护对策。研究结果表明:沿空留巷直接顶内的垂直应力和水平应力变化剧烈程度明显大于基本顶;围岩及充填墙体受力变化受3311工作面回采滞后采动应力作用明显,且主要对垂直应力的变化产生影响;3313工作面二次采动阶段,巷道围岩的变形受采动影响的敏感性远大于受力,即在充填墙体和巷道围岩应力增加很小的情况下,巷道变形增幅却相对较大,且主要表现为底鼓和两帮移近。井下试验表明,采用锚杆锚索与充填墙体联合支护后,通过优化现场施工工艺,沿空留巷满足了回采工作面的通风需求,降低了巷道掘进成本,实现了回采工作面快速推进。

Taking the gob-side entry retaining at the working face 3311 at Hexi coal mine as the background and using FLAC^（3D） finite difference program, this paper has calculated and analyzed the distribution characteristics of stress and deformation in the gob-side entry retaining surrounding rock, filled wall and coal pillars, and proposed reasonable support methods for the gob-side entry retaining. The research results have shown that： the fierce degree of the vertical stress and horizontal stress change in the immediate roof is obviously bigger than that in the main roof for the gob-side entry retaining; the mechanical change of the surrounding rock and filled wall is obviously influenced by the hysteresis mining-induced stress after the mining of the working face 3311 and the main impact is on the vertical stress change; at the second mining phase of the working face 3313, the deformation of the roadway surrounding rock caused by the mining influence at this phase is much more sensitive to the influence of the stress, which means after the action of the second mining stress, while the stress in the filled wall and the roadway surrounding rock increases moderately, the roadway deformation increases relatively significantly and is mainly in the form of convergence of floor heave and ribs. The underground test has indicated that with the combined support of the bolt, cable bolt and filled wall and optimized onsite construction, gob-side entry retaining has met the ventilation requirement of the mining face, reduced the cost of the roadway exaction and realized the rapid advancement of the mining face.