高瓦斯矿井内错顶板瓦斯巷合理布设及应用

Reasonable layout and application of inner dislocated gas roadway at the first mining working face with high gas mine

为解决高瓦斯矿井首采面回采巷道掘进期间瓦斯超限难题,采用数值模拟、地质力学模型试验、钻孔窥视研究手段,以支护受力、围岩偏应力、围岩变形与塑性区为分析立足点,获得了内错顶板瓦斯巷合理留设方案。结果表明:(1)围岩偏应力能较好地体现围岩抗屈服变形能力;偏应力演化规律与支护受力、围岩位移及塑性区扩延特征基本吻合;(2)水平巷间距6~8 m,锚杆支护能有效发挥长期承载能力,围岩抗屈服变形能力较强,巷间煤岩体具有良好的增透性;(3)轨道巷顶板裂隙分布范围为0.5~3.5 m,左帮煤体为0.5~2.6 m;(4)轨道巷顶板、帮煤岩体裂隙分布特征窥视结果与数值分析、模型试验研究结论较为吻合。现场应用表明,水平巷间距8 m能够实现两巷围岩稳定,提高瓦斯抽采率,满足了矿井安全、高效的生产要求。

Taking supporting force,deviatoric stress,surrounding rock deformation,and plastic zone as the analysis points,numerical simulation,geomechanical model test,borehole imaging methods were utilized to solve the difficult problem of transfinite gas phenomenon during excavation of mining roadway at the first mining working face of high gas mine,and the reasonable layout of the gas roadway was determined. The results show that the deviatoric stress can reflect the resistance to yield deformation of surrounding rock well; the evolution law of deviatoric stress matched well with characteristics of supporting force,surrounding rock deformation,and plastic zone. When the horizontal space is from 6 m to 8 m,the anchorage bolt can exert long-term bearing capacity effectively,and the resistance to yield deformation capability of surrounding rock is strong. So the permeability of surrounding rock is very good. The range of distribution fissure in roof is from 0. 5 m to 3. 5 m,while the left side is from 0. 5 m to 2. 6 m. The distribution characteristics of fissure in roof of roadway and side coal mass from borehole observation are similar with results from numerical simulation and geomechanical model test. Field application shows that 8 m horizontal roadway spacing can ensure the stability of both lanes,improve the gas drainage efficiency and satisfy the requirements and efficient production.