石门掘进为快速安全地揭煤通过煤层,依据"四原则"前探钻孔布置及"三点法"探孔资料分析并融合"后视点"、"截流抽采"等技术,提出了"五步法"预抽钻孔设计方法。实践结果表明:"四原则"前探钻孔布置方式可准确探明煤层赋存情况,按"五步法"预抽钻孔设计方法可保证钻孔施工的准确性,孔深误差±3 m,可消除由于钻孔施工不准而导致抽采瓦斯空白带的出现,有效抽采揭煤区域瓦斯及石门安全掘进顺利通过煤层。

In order to expose coal and through the coal seam quickly and safely when drainage in cross-cut, according to four principles for arrangement of advanc e detect borehole, and three-point method for analysis on the boreholes data, as well as the technical points of back sight point and closure drainage, the five-step pre- drainage borehole design method contains was put forward.Practical results showed that the arrangement of advance detect borehole based on the four principles can be accurately ascertain the coal ocurrence in the case of proven regional. The five-step pre-drainage borehole design method could ensure the accuracy of the borehole construction, hole depth error could be controlled within +3 m, it could eliminate the gas blank zone caused by inaccurate borehole construction, and it was good for pre -drainage in uncovering coal area and roadway driving.