密集抽采钻孔及浸水蠕变作用下底抽巷围岩控制技术研究

Surrounding rock control technology of floor gas extraction roadway under the action of dense drainage boreholes and water immersion creep

针对长平矿底抽巷变形大、服役期短和存在潜在冒顶风险等问题,提出了“型钢预应力注浆锚索网喷”综合控制技术。采用现场测试、室内实验方法,明确了底抽巷泥岩的结构特性和强度特性,揭示了裂隙化泥岩底抽巷的失稳机制,基于数值模拟和现场试验结果验证了所提围岩综合控制技术的有效性。结果表明:长平矿3号煤底抽巷泥岩具有结构裂隙化、强度低、易风化、浸水软化、蠕变特性显著的特征;以预应力注浆锚索为核心的“型钢预应力注浆锚索网喷”综合控制技术可较好地控制密集抽采钻孔和浸水软化蠕变耦合扰动下裂隙化泥岩底抽巷的围岩变形,使得底抽巷长期安全服役,有效解决了长平煤矿穿层瓦斯治理和采掘接续紧张问题,保障了工作面的安全高效回采。

In view of the large deformation,short service life and roof caving risk of the floor extraction roadway in Changping Coal Mine,a comprehensive control technology of steel prestressed grouting anchor cable net shotcrete is put forward.Through field test and laboratory test,the structural and strength characteristics of mudstone in the roadway were clarified,and the instability mechanism of fractured mudstone was revealed.The effectiveness of the proposed comprehensive control technology was verified based on numerical simulation and field test.The results show that the mudstone of No.3 coal floor gas extraction roadway has the characteristics of structural fissure,low strength,easy weathering,water softening and prominent creep.The deformation of floor drainage roadway induced by dense boreholes and water immersion creep can be well controlled by the proposed surrounding rock control technology,which ensures the safe and efficient mining.