极薄保护层钻采上覆煤层透气性变化及分布规律  

The change and distribution law of outburst coal seam permeability induced by drilling an extra-thin protective coal seam

作　　者：刘海波[1,2] 程远平[1,2] 宋建成[3] 尚政杰[1,2] 

机构地区：[1]中国矿业大学煤炭资源与安全开采国家重点实验室,江苏徐州221008 [2]中国矿业大学煤矿瓦斯治理国家工程研究中心,江苏徐州221008 [3]郑州煤炭工业(集团)有限责任公司,河南郑州452371

出　　处：《煤炭学报》2010年第3期411-416,共6页Journal of China Coal Society

基　　金：国家重点基础研究发展计划(973)基金资助项目(2005CB221503);国家自然科学基金重点项目(70533050);国家自然科学基金资助项目(50674089);国家"十五"科技攻关项目(2005BA813B-3-06)

摘　　要：为了分析极薄保护层钻采的卸压保护效果,采用相似模拟和现场试验相结合的研究方法,系统研究了被保护层卸压前后煤层透气性变化及分布规律。相似模拟试验研究表明,极薄保护层钻采后,被保护层产生卸压膨胀变形,煤层透气性增大,煤层透气性系数由3.80 m2/(MPa2.d)增大到7.11 m2/(MPa2.d)。上覆煤岩体移动稳定后,由于煤岩体应力逐渐恢复,煤层透气性系数降至5.61 m2/(MPa2.d),在保护层始采线前方和停采线后方的一定范围内上覆被保护层透气性比采空区中部大。随着被保护煤层逐渐被压实,煤层透气性有所降低,为了达到最佳的瓦斯抽采效果,必须在保护层钻采的同时进行卸压瓦斯抽采。现场实测极薄保护层钻采后被保护层透气性系数由0.047 m2/(MPa2.d)增加到18.928 m2/(MPa2.d),提高了403倍。Similarity simulations and field tests were used to investigate the change in seam permeability and the permeability distribution rule of the protected coal seam before and after pressure relief in order to analyze the pressure-relief protection effect of extra-thin protective coal seam mining.The similarity simulation tests show that the protected coal seam undergoes expansion deformation in the stress-relaxed area after the extra-thin coal seam is drilled.The permeability coefficient of the protected coal seam is increased from 3.80 to 7.11 m^2/（MPa2·d）,and after the overlying coal-rock mass has become stable,the permeability coefficient of the coal seam decreases to 5.61 m^2/（MPa2·d） because of stress recovery in the coal-rock mass.The protected coal seam permeability in a certain extent before the open-off cut and after the stopping line is higher than it in the middle of the goaf.With the protected coal seam being gradually compacted,the seam permeability decreases.In order to achieve the optimal effect of gas drainage,the extra-thin protective coal seam drilling combined with pressure relief gas drainage of the protected coal seam must be adopted.Field tests show that the permeability coefficient of the protected coal seam increases from 0.047 to 18.928 m^2/（MPa2·d）,an increase of 403 times.

关 键 词：极薄保护层 被保护层 煤层透气性 相似模拟 卸压 

分 类 号：TD712.6[矿业工程—矿井通风与安全]