开采煤层顶板环形裂隙圈内走向长钻孔法抽放瓦斯研究

开采煤层工作面的瓦斯主要来源于该煤层、采空区和邻近层的卸压解吸瓦斯。由于煤层松软，顺层钻孔施工难，不便钻孔抽放瓦斯。若对采空区实施大面积抽放，工程难度大，而且抽不出高浓度瓦斯。因此，寻找瓦斯运移的裂隙通道和瓦斯富集区，实施有效的瓦斯抽放工程是实现高效瓦斯抽放的技术关键。采用实验室相似材料试验、数值模拟计算和工业性试验研究方法，研究寻找采场上覆岩层中环形裂隙圈形成机理和位置，把抽放钻孔布置在环形裂隙圈内，进行“环形裂隙圈内走向长钻孔法”瓦斯抽放。这种瓦斯抽放技术使低透气性高瓦斯煤层的开采和瓦斯抽放分层区进行

Study on Coal Seam Roof Gas Drainage from the Strike of Annular Fracture Areas by the Long Drill Method

Gas in working faces is mainly produced in the destressing and desorption process of the coal bed,gobs and adjacent strata.The coal beds are too soft to carry out bedding drilling and draw gas effectively.If gob gas suction is adopted in a large area,the project will prove not only extremely difficult,but also fail to draw out gas of high concentration.Therefore,efficient gas suction is technically determined by seeking fracture aisles for gas movement and gas zone of enrichment.In the course of mining and destressing, gas originating from large destressing areas will go through the fracture aisles of the full development areas and gather in annular fracture areas.The similar material experiments in the laboratory,the numerical simulation and the in-situ study are applied in this work in order to find the location of annular fracture areas in overlying formation.The long-drill mehtod for gas suction along the strike of annular fracture areas is adopted.Mining in coal beds with gas of high conentration and low permeability and gas suction can be operatod separately. During mining activities in the working faces,gas released from roof fracture areas will not flow into upper corners,so the technically drilling problem in soft coal beds with low permeability and high concentration gas can be solved.The application of this technology in the working faces of the gassy mines in Huainan shows that gas suction rate is above 60 percent, making it possible to mine safely,efficiently and intensively.