构造破碎区沿空掘巷偏应力分布特征与控制技术

Distribution characteristics of deviatoric stress and control technology of gob-side entry driving in structure fracture zone

以黄岩汇煤矿15111轨道巷为工程背景,采用数值模拟、实验室试验及现场实测等方法,研究了构造破碎区沿空掘巷围岩偏应力分布特征及控制技术。结果表明:随着煤柱宽度的增加,巷道围岩偏应力峰值及峰值位置均有较大变化,偏应力峰值变化幅度由大到小为煤柱帮(20 MPa)、顶板(4.6 MPa)、底板(2.6 MPa)、实体煤帮(2.5 MPa);峰值位置变化幅度由大到小为底板(4.25 m)、顶板及煤柱帮(3 m)、实体煤帮(0.25 m);沿空掘巷巷道开挖引起的偏应力在15 MPa以上,在其作用下围岩发生大范围剪切破坏,构造破碎区围岩易崩解破碎,更加剧了巷道失稳,支护不合理时容易出现顶板冒落、煤帮垮塌和强烈的底鼓现象。据此,提出了包括高密度长锚索控制顶板稳定、大直径短锚索替代帮部锚杆、设置帮角加强锚杆及破碎煤体的锚注加固在内的综合控制技术。现场应用表明该技术能有效控制巷道变形,实现构造破碎区沿空巷道的稳定性控制。

Taking the tailgate of panel 15111 in Huangyanhui colliery as the engineering background, the distribution characteristics of deviatoric stress and control technology of gob-side entry driving in structure fracture zone were investigated through numerical simulation, laboratory tests and field moni- toring. The results showed that the peak deviatoric stress and its position change significantly with the increase of pillar width; the change ranges of the peak deviatoric stress descend from pillar rib （20 MPa） to roof （4.6 MPa）, floor （2.6 MPa）, and to coal rib （2.5 MPa）, and the change range of position of the peak deviatoric stress from floor （4.25 m） to roof and pillar rib （3 m）, and further to coal rib （0.25 m）. Under the influence of the deviatoric stress of gob-side entry driving above 15 MPa caused by excavation, a large range of shear failure occurred in surrounding rock and the surrounding rock in structure fracture zone was subject to crumbling and breakage, which exacerbated the roadway instability, and the roadway was prone to roof caving, rib collapse and heavy floor heave when the support parameters were not reasonable. Accordingly, a synthetical control technology was put forward, including roof control with highdensity long anchored cables, rib control with large-diameter short cables, corner control with intensive anchors, and bolting and grouting method used in the broken coal-mass area. Field application has shown that this technology can effectively control the deformation of surrounding rock and guaran- tee the stability of gob-side entry roadway in structure fracture zone.