采空区水平钻孔瓦斯抽放工艺与原理

针对采空区瓦斯抽放问题,讨论抽放钻孔布置、工艺特点及抽放原理。水平钻孔抽放的优点是可选择高的钻孔位置,能获得更大的瓦斯抽放浓度,可提高抽放效率。钻孔应选择在较坚固的岩层中,避免塌孔或遇到断层等构造破碎带。提出采空区水平钻孔瓦斯抽放模拟计算方案,计算了瓦斯抽放时流场风流规律。抽放时,工作面向采空区的漏风流,在下游回风段形成了上、下分流。模拟试验中,在扩大抽放流量时,能加大工作面向采空区的总体漏风量,而降低了采空区向工作面的漏回风量;随着抽放流量的增大,工作面与采空区风流交换平衡点向回风侧移动。由此给出抽放流量等于总漏回风量的绝对安全抽放关系准则,为确定瓦斯抽放流量及抽放浓度提供依据。

Study on relief and drainage of coal-gas from horizontal drill-holes in goaf field

To the question of drilling level holes in goaf field for gas drainage, the location of the holes, the feature of the craft and the principle of drainage were discussed in this paper. The strongpoint of level drill-hole drainage is that the holes can be placed on higher position, then can obtain larger gas drainage concentration and improve the efficiency. The position of the drill-holes should be in the harder terrenes, in order to avoid the holes collapsing, or meeting fauhage or other fracture zones of geological structure. A simulation calculation scheme for gas drainage in goaf was proposed, then a conclusion that the leak-in volume will increase and the leak-out volume will reduce as enlarging the drainage flux was drawn through the simulation experiments. Distributaries of the leakage from the workface to the goaf field were formed at the upward return laneway. Finally, the safe relation rule between the drainage flux and the leak-out volume was proposed, that is the drainage flux should not more than the leak-out volume, which is a gist for confirming the gas drainage flux and drainage concentration.