Stress-unloading and gas migration improvement mechanism in the soft and hard interbedded coal seam using directional hydraulic flushing technology

作     者：Hao Zhang Yuanping Cheng Cunbao Deng Jingyu Jiang Lei Zhang Xiaoyu Yan Junwei Guo Suifang Wang Hao Zhang;Yuanping Cheng;Cunbao Deng;Jingyu Jiang;Lei Zhang;Xiaoyu Yan;Junwei Guo;Suifang Wang

作者机构：College of Safety&Emergency Management EngineeringTaiyuan University of TechnologyTaiyuan 030024China Datong Coal Mine Group Co.LtdDatong 037037China Key Laboratory of Coal Methane and Fire ControlMinistry of EducationChina University of Mining and TechnologyXuzhou 221116China National Engineering Research Center for Coal and Gas ControlChina University of Mining and TechnologyXuzhou 221116China School of Safety EngineeringChina University of Mining and TechnologyXuzhou 221116China 

出 版 物：《International Journal of Mining Science and Technology》 (矿业科学技术学报(英文版))

年 卷 期：2023年第33卷第9期

页      面：1165-1179页

核心收录：

学科分类：0819[工学-矿业工程] 081903[工学-安全技术及工程] 08[工学] 

基　　金：the financial support from the National Natural Science Foundation of China(Nos.52104210,52174217,and 51874294) the Natural Science Foundation of Shanxi Province(No.20210302124350) Project Funded by China Postdoctoral Science Foundation(No.2022M710595) 

主　　题：Hydraulic flushing Stress-unloading Plastic failure Permeability-increasing Gas migration 

摘      要：To enhance gas drainage in the soft and hard interbedded(SHI)coal seam,it’s necessary to unload the insitu stress and improve its gas migration *** this research,a directional hydraulic flushing(DHF)technology was carried *** stress-unloading and gas migration improvement mechanism was analyzed through numerical simulation,and systematic engineering tests were conducted to verify the gas drainage *** results show that the improvement of gas migration performance in the SHI coal seam is caused by a combined effect of seepage-improving and *** DHF,stress-unloading and plastic failure could be achieved both in the soft coal(SC)sublayer and in the hard coal(HC)***,the gas diffusion capacity improves significantly in the SC sublayer,while the gas seepage capacity improves notably in the HC ***,the stress-unloading and gas migration improvement effect improves with the flushing radius and the thickness of the SC ***,after adopting the DHF technology,the gas drainage effect improved *** borehole number dropped by 49%,the gas drainage ratio increased from 26.0%to 48.2%,and the average coal roadway excavation speed increased from 2.4 to 5.6 m/d.