影响采空区顶板抽放瓦斯效果的主要因素分析

Study on the calculation of the gob roof cracks structure and applying gas drainage

对于低透气性高瓦斯煤层群开采的首采工作面,或厚煤层开采一分层的工作面回风流中的瓦斯浓度超限问题是一大难题,为解决此难题,通常采用顺层钻孔、穿层钻孔抽放瓦斯措施,收到了一定的效果,问题尚得到较好解决。开采煤层工作面的瓦斯主要来源于本煤层、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,不便进行顺层钻孔抽放瓦斯,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。煤层回采后,采空区顶底板岩层卸压,产生裂隙。由于瓦斯的升浮漂移和渗流特性,来自于开采煤层和卸压煤层内卸压瓦斯,沿裂隙通道汇集到裂隙区,形成瓦斯积存库。把抽放钻孔或巷道布置在顶板裂隙内,实施瓦斯抽放,该抽放瓦斯技术起到了对开采工作面上隅角瓦斯的截流作用,解决了松软低透气性高瓦斯煤层群开采瓦斯抽放困难的关键技术难题。

To solve the problem of exceeding gas concentration in the mining and distressing areas, the method of simulated calculation of numerical value and industrialized experimental research is applied in the thesis in overlying formation. Due to its characteristics of floating and seepage, gas from large destressing areas would pass through facture aisles and gather in annular fracture areas and form a stock of gas. The method of long-drill of gas suction in the annular fracture areas, which can stop the flowing of the gas to upper corners, properly solved the technical problem of gas suction in soft coal beds.