空间孤岛岩柱区特厚煤层整体卸压防冲−防突协同控制技术

    Integrated pressure relief technology for rock burst and gas outburst coordinated control in ultra-thick coal seams under spatially isolated rock pillar areas

    • 摘要: 随着煤炭开采深度与开采技术条件复杂性的增加,部分矿井面临冲击地压和煤与瓦斯突出双重动力灾害,且呈现相互耦合诱发趋势。以典型冲击−突出矿井为工程背景,研究了受油页岩开采形成的空间“孤岛岩柱”影响下特厚煤层应力分布规律,提出了顺层超深大直径钻孔与穿层超高压水力割缝区的区域整体卸压技术。研究结果表明:油页岩采空区下煤层巷道的垂直应力较低,均小于4 MPa,保护层卸压作用显著;空间岩柱区域巷道垂直应力峰值接近20 MPa,是保护层下方垂直应力的5.0倍,且应力集中范围大,呈区域高应力状态;相比于传统“边掘边卸”技术方案,超前整体卸压降低了巷道周边支承压力峰值,消除了卸压盲区,孔、缝周边煤体变形、破裂后,孔内坍落煤体被及时排出,卸压区域煤体完整性显著降低,裂隙发育程度远高于常规卸压,被完全压实的可能性大大减小,同时提高了卸压时效性;整体预卸压状态下,钻孔直径200 mm、间距0.5 m的情况下,巷道围岩变形量小于边掘边卸技术方案;岩柱影响区域内,巷道掘进与回采期间微震频次与能量均呈现稳定状态,矿震总能量与非煤柱影响区相比呈下降趋势,冲击危险等级以弱为主,测试煤层残余瓦斯含量降低至4.73 m3/t,防冲−防突效果显著。

       

      Abstract: With the increasing depth of coal mining and the complexity of mining technical conditions, some mines are facing dual dynamic disasters of rock burst and coal and gas outburst, which exhibits a mutually coupled inducing trend. This study took a typical rock burst and gas outburst coal mine as the engineering background, studied the stress distribution law of extremely thick coal seam under the influence of the space “isolated rock pillar” formed by oil shale mining, and proposed the regional integrated pressure relief technology along the seam with ultra-deep and large diameter drilling and through the ultra-high pressure hydraulic slotting zone. The results indicate that: the vertical stress of the roadway in the coal seam under oil shale goaf is relatively low (all below 4 MPa), demonstrating significant pressure relief effects from protective seams; in spatial rock pillar influencing areas, the vertical peak stress of the roadway approaches 20 MPa, five times higher than that under protective seams and the stress concentration range is relatively larger than normal, which exhibits a state of regional high stress. Compared with traditional “pressure relief along with excavation” modes, integrated pre-pressure relief can reduce peak abutment pressure around roadways, eliminate pressure relief blind zones, significantly decrease the compaction possibility and enhance pressure relief timeliness. In 200 mm borehole diameter and 0.5 m spacing in integrated pressure relief conditions, roadway deformation becomes smaller than that in traditional scenarios; both micro seismic frequency and energy remain stable during roadway excavation and coal mining in rock pillar affected areas, with measured residual gas content decreasing to 4.73 m3/t, demonstrating remarkable combined rock burst and gas outburst prevention effects.

       

    /

    返回文章
    返回