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针对我国中东部煤田煤层群埋藏深、煤质软、瓦斯压力和瓦斯含量高、瓦斯难以抽采的难题,利用数值模拟和现场工程试验相结合的方法,系统的研究了高瓦斯煤层群首采层“Y”型通风瓦斯抽采技术。研究获得了煤层开采上覆围岩裂隙演化特性规律以及垂向位移与下沉规律,探明了在10倍采高层位处的上覆岩层离层裂隙及纵向裂隙最发育,此处形成了瓦斯富集区,并同时形成了相互沟通的裂隙网为瓦斯抽采提供了运移通道。设计了大直径钻孔组瓦斯抽采方法,综合利用大直径钻孔组和采空区埋管技术,使得顶板裂隙带内的卸压瓦斯以及采空区内的瓦斯得以高效抽采,回风流中的瓦斯浓度控制在0.3%以下,实现了利用大直径钻孔组代替倾向高抽巷高效抽采瓦斯的目的。
In view of the problems that the coal seams in the eastern and central coalfields are deeply buried, the coal quality is soft, the gas pressure and gas content are high, and the gas is difficult to be extracted, the numerical simulation and field engineering tests are combined to systematically study the first mining Floor “Y ” type ventilation gas pumping technology. The law of evolution and law of vertical displacement and subsidence of overlying rock in coal mining are obtained. It is proved that the overlying and longitudinal cracks in the overlying strata are most developed at 10 times of mining high level, where gas is formed Enrichment area, and at the same time formed a network of fissures that communicate with each other to provide a migration channel for gas drainage. The gas drainage method for large-diameter drilling group is designed. The technology of large-diameter drilling group and gob-burying pipe are comprehensively used to make the relief gas in the roof fracture zone and the gas in the gob area to be efficiently extracted and return air flow In the gas concentration control below 0.3%, to achieve the use of large-diameter drilling group to replace the high-efficiency gas drainage tunnel pumping efficiency purposes.