For researching the technologies of rock cross-cut coa uncovering and avoiding outburst of gas in condi-tion of soft coal seams with strong gas outburst in short distance , meanwhile for uncovering coal safely and smooth-ly, the gas of 9 +8 coal seam was extracted by pre-extraction drilling and hydraulic flushing in condition of low pressure in order to avoid the outburst of coal and gas based on the geological condition and gas occurrence of Ⅱ32 main cross-cut in Haizi Coal Mine .The results showed that:When the rate of impulse coals reaches 4.5%, the gas flow becomes 10 times than that before punching .Meanwhile , the whole rate of gas extraction increases 1.6 times which reaches 71.7%and the effect of pressure relief and enhanced gas permeability is remarkable .After pre-ex-traction drilling, the residual gas pressure of Coal 9 is 0.3Mpa, for Coal 8 it is 0.22Mpa.The gas remainder quan-tity of Coal 9 is 5.23m3/t, for Coal 8 it is 5.13m3/t.It can uncover the 9+8 coal seam safely and smoothly , and the effect of avoiding outburst is significant .%为了研究强突松软近距离煤层群石门揭煤防突技术，安全、顺利地揭煤，基于海孜矿Ⅱ32主运石门地质条件和瓦斯赋存状况，对近距离煤层群9＋8煤层实施密集预抽钻孔抽采瓦斯与低压水力冲孔卸压增透相结合的措施，防治煤与瓦斯突出。结果表明：低压水力冲孔冲煤率达到4.5％；冲孔后瓦斯抽采流量为未冲孔的10倍以上；整体瓦斯抽采率达到71.7％，比以前提高了约1.6倍，卸压增透效果明显。预抽钻孔抽采后，9煤、8煤的残余瓦斯压力，分别为0.3MPa、0.22MPa，残余瓦斯含量分别为5.23m3/t、5.13m3/t，防突效果显著，可安全、顺利地揭开9＋8煤层。
展开▼
