According to technical problem of the long-distance under-protecting No.11 Coal seam's pressure relief gas drainage in Sangshuping Coal Mine,against engineering background of protecting No.3105 coalface,to use numerical simulation and spot observation,research on protected No.3 coal seam's stress field evolution law,expansion deformation distribution,pressure relief gas drainage holes layout,time-space law of pressure relief gas drainage.Researches showed that,compression zone,expansion deformation zone,sufficient expansion deformation zone expansion deformation zone and compression zone distribute along coal seam's strike,gas drainage holes layout on different distance,holes constrict advance 30 meters before protecting coalface,pressure relief gas drainage active zone was the zone before 10 meters and behind 60 meters protecting coalface,the pressure relief drainage time sustains thirty to forty days,protected seam's gas drainage efficiency was sixty percent.Research result provided scientific basis for the long-distance under-protecting coal seam's pressure relief gas drainage.%针对桑树坪煤矿远距离下保护层11号煤层开采卸压瓦斯抽采的技术难题,以矿井3105保护层工作面为工程背景,采用数值模拟、现场考察的方法,研究了被保护层3号煤层应力场演化规律、膨胀变形分布、卸压瓦斯抽采钻孔合理布孔位置及卸压抽采时空规律.研究表明:沿煤层走向变形区域分为压缩区—膨胀区—充分膨胀区—膨胀区—压缩区,抽采钻孔应非等间距布置;走向方向抽采钻孔施工超前保护层工作面煤壁距离应大于30 m;被保护层在保护层工作面前方10 m至后方60m区域为卸压瓦斯抽采活跃区;卸压瓦斯抽采区时间持续30～40 d,被保护层瓦斯预抽率可达60％.研究成果为远距离下保护层卸压瓦斯抽采提供了科学依据.
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