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工作面采动煤体卸压增透效应研究及应用
探讨
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王凯,郑吉玉
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基金项目:高等学校博士学科点专项科研基金博导类资助课题(20120023110006);国家自然科学基金项
目(51174212)
作者简介:王凯(1972—),男,河南遂平人,教授,博士生导师。从事安全工程技术、矿业灾害防治方面研究.
E-mail: wkcumt@126.com
(中国矿业大学(北京)资源与安全工程学院,北京 100083) 5
摘要:分析了采煤工作面前方采动煤体变形破坏与渗透性变化过程的相关性,在工作面前方
卸压区,煤体发生滑移破坏,有明显的扩容及卸压增透效应。现场实测了工作面前方煤体应
力及钻孔瓦斯流量随工作面推进过程的变化规律,确定了支承压力区、卸压区分布范围;在
卸压区内,因煤体渗透率增大钻孔瓦斯平均流量提高 2~3 倍。基于工作面前方煤体卸压增10
透效应,根据不同钻孔失效距离及卸压区宽度,给出了不同偏角下的预抽钻孔卸压瓦斯抽采
量计算公式,分析表明:钻孔偏角越大,卸压瓦斯抽采量越大。结合某矿 N2105 工作面现
场条件进行计算,钻孔偏角最大可为 21.4°,相比原垂直煤壁钻孔,单孔卸压瓦斯抽采量可
增加 978.5 m
3
,预期可有效提高本煤层瓦斯抽采率。
关键词:工作面;采动煤体;卸压增透效应;应用 15
中图分类号:TD712
Study on destressing and permeability-increasing effect of
mining-affected coal ahead of coal face and its application
WANG Kai, ZHENG Jiyu 20
(School of Resoure and Safty Engineering,China University of Mining and Technology(Beijing))
Abstract: Analysis of correlation deformation failure and permeability changes ahead of mining
face. Ahead of working face of destressing zone, coal slip failure, have a marked expansion and
destressing and permeability-increasing effect. Field measurement the change of stress and bore
hole gas flow ahead of working face, determined the abutment pressure zone, destressing zone 25
distribution. In distressing zone, because the permeability of coal increases, the average flow of
gas is increased by 2~3 times. Based on destressing and permeability-increasing effect ahead of
coal face, according to the different bore hole failure distance and destressing zone width, given
the different angle of pre drainage bore hole destressing gas drainage quantity formula. Analysis
shows that: bore hole angle increases, destressing gas drainage amount larger. Combined with 30
field condition of N2105 face in a mine to calculate, the maximum hole angle is 21.4 °,
Compared with the original vertical coal wall bore hole, destressing gas drainage can increase
978.5 m
3
of single bore hole, expectations can effectively improve the coal seam gas drainage rate.
Key words:
coal face;mining-affected coal;destressing and permeability-increasing effect;
application
35
0 引言
经过长期的地质演化,煤体及煤层瓦斯在地层中处于平衡状态。受采动影响,工作面前
方煤体的水平应力表现为卸压过程,而在铅直方向上煤体则依次经历了原始应力阶段、支承
压力阶段和卸压阶段
[1]
。原始应力阶段,煤体渗透率处于未受到采动影响的正常水平;支承40
压力阶段,煤体中的原生裂隙闭合,渗透率降低;卸压阶段,煤体发生卸压破坏,裂隙发育,
煤体渗透率增大。尤其在卸压阶段后期,因水平应力降低发生明显的扩容现象,煤体渗透率
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