摘要
为了解决五轮山煤矿8号高突低渗透煤层1809工作面瓦斯治理难题,提出了超高水力割缝煤层卸压增透技术,以有效改造强化瓦斯抽采。采用理论分析、FLAC^(3D)数值模拟方法研究了不同缝槽间距条件下缝槽周围煤体塑性破坏特征和应力演化规律,然后基于含瓦斯煤体渗透率与三向应力和瓦斯压力之间的关系,分析了不同缝槽间距时周围煤体的渗透率分布规律。研究结果表明:缝槽自由面能够卸除围压,集中应力向缝槽外侧和缝槽间煤体转移;煤体渗透率明显提高,促进瓦斯解吸和流动。经现场实践验证,超高压水力割缝增大了煤层暴露面积、煤体扰动体积,高负压抽采支管瓦斯流量和浓度明显提升,瓦斯抽采纯量在0.7～1.1 m^3/min内波动,瓦斯体积分数在50%以上,对本矿其他工作面瓦斯治理具有一定借鉴意义。
Aiming at solving the problem of gas control in high outburst and low permeability coal seam of No. 8 coal seam in Wulunshan Coal Mine No. 1809 coal mining face,this paper proposes a gas extraction technology using ultra-high hydraulic slotting in coal seams. The plastic failure characteristics and stress evolution of coal around the hydraulic slots under different slot spacings are analyzed theoretically and numerically.The numerical simulation is conducted using FLAC 3D . Then, based on the relationship between gas permeability and triaxial stress and gas pressure, the permeability distributions of coal around the hydraulic slots are analyzed. It is found that the free surface of hydraulic slots can reduce the confining pressure around the slots, which results from the concentrated stress transferring to the area outside of the slots and the coal between the slots. Coal permeability is significantly increased, followed by the increase of gas desorption and gas flow. The field practice shows that the ultra-high pressure hydraulic cutting increases coal exposed area and coal disturbance volume. The gas flow rate and gas concentration of high negative pressure extraction pipes are then significantly increased. The field measurement data shows that the pure quantity of drainage is between 0.7 and 1.1 m ^3/min and the gas concentration is above 50%. This paper provides reference for gas control in other working faces of the mine.
作者
张帅
刘志伟
韩承强
位乐
章飞
ZHANG Shuai;LIU Zhiwei;HAN Chengqiang;WEI Le;ZHANG Fei(National Laboratory of Gas Monitoring and Emergency Response Technology,Chongqing 400037,China;China Coal Technology and Engineering Group Chongqing Research Institute,Chongqing 400037,China)
出处
《煤炭科学技术》
CAS
CSCD
北大核心
2019年第4期147-151,共5页
Coal Science and Technology
基金
国家重点研发计划资助项目(2017YFC0804208)
关键词
超高压水力割缝
塑性破坏特征
应力演化
渗透率分布
ultra-high pressure hydraulic slotting
plastic failure characteristics
stress evolution
permeability distribution
