厚煤层孤岛煤柱内合理掘巷位置及支护技术研究

Study on the reasonable tunnelling position and supporting technology of the roadway in isolated coal pillar of thick coal seam

针对孤岛煤柱内掘巷位置及支护技术选择不当,极易导致巷道变形严重难以维护的问题,以新疆某矿为工程背景,运用数值计算的方法分析了厚煤层孤岛煤柱应力分布规律和孤岛煤柱内巷道的围岩变形特征。结果表明:孤岛煤柱在后开采工作面一侧的应力降低区宽度大于先开采的一侧;孤岛煤柱巷道在宽煤柱侧顶帮的围岩变形量显著高于窄煤柱侧,具有非均匀性。结合理论计算和数值分析结果,确定试验巷道的合理位置是在5 301采空区侧留设4.0m窄煤柱沿底板掘进。同时,针对孤岛煤柱内巷道围岩的非均匀变形特征及煤柱整体较破碎的特点,提出采用高强螺纹钢锚杆加长锚固和关键部位锚索加强支护相结合的非对称支护技术,经现场应用验证了方法和技术的有效性。

Aiming at the problems that surrounding rock of the roadway in isolated coal pillar were deformed seriously and difficult to maintain,which caused by improper position and support technology.Based on the engineering background of a mine in Xinjiang,the stress distribution law of the isolated coal pillar and the deformation characteristics of the surrounding rock were analyzed by the method of numerical simulation.It was found that the width of stress reduction area which located on the side of the second coal face is larger than that of the first one.And,the surrounding rock deformation of the roof and coal side which located near the wide coal pillar is significantly higher than that of located near narrow coal pillar,which distributes homogeneously.According to the theoretical calculation and numerical analysis results,the reasonable tunnelling position of the test roadway was determined to be in the side of the 5 301 gob area to keep 4.0 m narrow coal pillar,and driving along the floor.At the same time,according to the characteristics that non uniform deformation of surrounding rock of the roadway in isolated coal pillar and the isolated coal pillar was crushed seriously,the asymmetric supporting technology was invented,which consist of lengthen anchorage by high strength thread steel bolt and reinforced support at the key position by anchor cable.Through engineering practice,the validity of this method and technology was proved.