15 m特厚煤层综放高强度开采窄煤柱围岩控制研究

Research on surrounding rocks control of narrow pillar with high-intensity fully-mechanized top coal caving mining in 15 m ultra-thick coal seam

针对塔山煤矿15 m特厚煤层综放开采留宽煤柱(38~45 m)护巷所带来的矿压显现强烈,煤炭损失严重等问题,提出15 m特厚煤层综放窄煤柱沿空掘巷技术。以8204面为工程背景,采用理论计算和钻孔窥视,确定基本顶断裂线位置距采空区煤壁为4 m,并对掘巷前基本顶弧形三角块结构稳定性进行分析,得到巷道应布置在基本顶断裂线以外及悬臂梁平衡结构保护下的应力降低区内,综合确定煤柱宽度为6 m。基于巷道的控制难点,提出高强度高预应力锚杆索、多锚索-钢带桁架、梯级锚固束锚索、钢筋混凝土防护墙、向窄煤柱和相邻面采空区注浆的强力联合支护技术。现场实践表明,巷道围岩控制效果较好,说明采用窄煤柱和强力联合支护技术是可行的。

In order to solve the problems of strong ground pressure and coal resource loss in Tashan Coal Mine due to retaining large coal pillar （38-45 m） to protect roadway with using fully-mechanized top coal mining for 15 m thick coal seam, the technology of gob-side entry driving with narrow coal pil- lar is put forward. Taking the 8204 fully-mechanized top coal mining face as an engineering case, by using theoretical calculations and borehole observation to ensure the location of the fracture line in the main roof is 4 m next to the gob. Meanwhile, based on the analysis of the structural stability of the arc triangular plate in front of the driving development head, the gob-side entry driving should be arranged out of the main roof fracture line and in the stress reduction area protected by the cantilever beam bal- ance struc^tre. Then, the reasonable pillar width is determined to be as 6 m. Based on the difficulties of roadway surrounding rock control, the powerful combined supporting technology consists of high strength and pre-stressed yield-pressure bolt and anchor cable, multiple cable-belt truss, step anchored bundled anchor cable, grouting narrow pillar and gob reinforcement and reinforced concrete protective wall is proposed. The field test shows that the control effects of the surrounding rock is well by using the narrow coal pillar and powerful combined supporting technology.