岩浆岩侵入区巨厚煤层掘进巷道冲击地压机制研究

Rock burst mechanism of heading roadway in thick coal seam in magmatic intrusion areas

针对岩浆岩侵入区采掘期间冲击地压频繁发生的实际问题,运用理论分析、数值模拟以及工程实践等研究方法,研究岩浆岩侵入区巨厚煤层掘进巷道冲击地压机制。主要结论如下:基于弹塑性理论推导出巨厚煤层巷道围岩应力分布计算公式,由此绘制应力分布等值线图,结果表明最大主应力方向、最大剪应力集中区位置均与煤层倾向相垂直,煤层倾角不能改变最大主应力和剪应力的集中程度,而侧压系数对最大主应力集中程度的影响较大。坚硬岩浆岩顶板在采空区上大面积悬顶导致其附近大面积煤体应力的整体升高,为冲击地压发生提供了静载荷;掘进施工诱发岩浆岩局部侵入带能量的瞬时释放,为冲击地压发生提供了动载荷;综上分析,建立岩浆岩侵入区巨厚煤层掘进巷道冲击地压的力学模型,得出冲击发生判据,进而获得冲击地压发生机制。应用研究成果,较好地分析了矿井实际掘进巷道冲击地压的发生机制,并有效地指导了冲击地压防治实践。

Rockbursts frequently occur during mining in magmatic intrusion areas. The mechanism of rock burst at heading roadway in thick coal seam in magmatic intrusion areas is thus studied theoretically and numerically. A formula for calculating the stress distribution in surrounding rock of the roadway was deduced based on the elastoplastic theory. The contours of stress distribution shows that the direction of maximum principal stress and the concentration area position of maximum shear stress were perpendicular to the inclination angle of coal seam. The dip angle of coal seam does not change the concentration degree of maximum principal stress and shear stress. The lateral pressure coefficient had a greater influence on the concentration of the maximum principal stress. The large hard magmatic rock roof suspending in the goaf leads to the overall increase of the stress in the large area of coal nearby,which provides the static loading for rockburst. Tunneling induces the instantaneous release of energy from the local magmatic rock,which provides the dynamic loading for rock burst. Based on the above analysis,the mechanical model of rock burst in roadway in thick coal seam in magmatic rock intrusion zone was established,the criterion of rockburst occurrence was obtained and then the mechanism of rockburst was obtained. The application of the research results guided the prevention of rock burst in practice.