基于钻孔影响半径的保护层卸压效果考察  

Analysis on pressure relief by protective layer mining based on borehole's influencing radius

作　　者：曹召丹[1,2] 林柏泉[1,2] 赵世伟 刘非非[1,2] 郝志勇[1,2] 

机构地区：[1]中国矿业大学安全工程学院,江苏省徐州市221008 [2]煤炭资源与安全开采国家重点实验室,江苏省徐州市221008 [3]郑州广贤工贸有限公司,河南省郑州市450000

出　　处：《中国煤炭》2012年第5期103-107,共5页China Coal

摘　　要：我国95%以上的高瓦斯和突出矿井所开采的煤层属于低透气性煤层,煤层透气性系数只有10-3～10-4 mD,未卸压瓦斯抽采难度非常大。保护层开采破坏了原岩应力平衡,地应力重新分布,煤层与岩体发生卸压、膨胀,并产生大小不同的裂缝,增大了透气性系数,可以提高抽采效率。采用压降法测定钻孔抽放影响半径,并对保护层开采的卸压增透效果进行评价,分析得出,在未卸压区域钻场抽放影响半径是单孔抽放影响半径的1.85倍,单纯的增加钻孔数量对抽放效率的提高有限;保护层开采将钻场有效影响半径由卸压前的3.7m提高到卸压后的5m,卸压增透效果明显。The coal seams in more than 95 % of coal mines with high-gas and gas outburst in our country are of low permeability. Low permeability coefficient in the range of 10^-3 mD to 10^-4 mD makes gas drainage difficult without pressure relief. The balance of original rock stress bro- ken by protective layer mining leads to terra stress redistribution, pressure relief and expansion of coal seams and rock mass, so the formed cracks in different sizes increase the permeability co- efficient so as to improve the gas drainage efficiency. The influencing radius of boreholes was measured by pressure dropping method. Moreover, in the region without pressure relief, the drainage radius is 1. 85 times of that for solo borehole, indicating limited enhancement of gas drainage efficiency by increasing borehole numbers. The effective gas drainage radius was in- creased from 3.7 m to 5 m before and after pressure relief via protective layer mining, with obvi- ous enhancement of gas permeability.

关 键 词：钻孔影响半径 压降法 保护层开采 抽放瓦斯 卸压增透 

分 类 号：TD712.6[矿业工程—矿井通风与安全]