基于PFC的上向远距离被保护煤层横向裂隙时空演化规律研究  

Research on spatial-temporal evolution law of transverse fractures in upward long-distance protected layer based on PFC

作　　者：石钰 邢珍珍 詹可亮 李树刚 赵鹏翔[1,2] 薛俊华 SHI Yu;XING Zhenzhen;ZHAN Keliang;LI Shugang;ZHAO Pengxiang;XUE Junhua(School of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an,Shaanxi 710054,China;Key Laboratory of Western Mining and Disaster Prevention and Control,Ministry of Education,Xi'an University of Science and Technology,Xi'an,Shaanxi 710054,China;School of Mechanical and Electrical Engineering,Huainan Normal University,Huainan,Anhui 232038,China)

机构地区：[1]西安科技大学安全科学与工程学院,陕西西安710054 [2]西安科技大学西部矿井开采及灾害防治教育部重点实验室,陕西西安710054 [3]淮南师范学院机械与电气工程学院,安徽淮南232038

出　　处：《采矿与安全工程学报》2025年第1期229-238,共10页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(11802231,52174205,51974239)。

摘　　要：为探究上向远距离被保护煤层横向离层裂隙时空演化规律,以平煤六矿采区开采戊8煤层向上保护丁5.6煤层为工程背景,采用相似物理模拟实验和PFC(Particle Flow Code)数值模拟相结合的方法,系统研究保护层开采过程中上覆煤岩体移动变形、被保护煤层采动裂隙发育及分布特征、被保护煤层应力时空演化规律,同时采用RFPA(Realistic Failure Process Analysis)数值模拟软件对被保护煤层的透气性进行分析。结果表明:卸压开采后,远距离上被保护煤层产生拉伸型横向裂隙,形成卸压瓦斯横向渗流通道。采动影响下,覆岩裂隙延伸出现分层现象,裂隙发育呈“梯形”,被保护煤层应力变化曲线从“V”形向“U”形转变,被保护煤层保护边界向保护层采空区方向内错约10~20 m,进入稳定卸压膨胀区域,煤层透气性显著提高,产生较强的“卸压增透”效应,此时为卸压瓦斯抽采最佳“时间窗口期”。This study is aimed at investigating the spatial-temporal evolutions of transverse separation fractures in the upper long-distance protected layer.To achieve this aim,Pingdingshan No.6 Mine where the Wu8 coal seam that is being mined acts as the protective layer and the upper Ding5.6 coal seam acts as the protected layer is taken as the engineering background.First,the movement and deformation of overlying coal rock mass,the development and distribution characteristics of mining-induced fractures in the protected layer,and the spatial-temporal evolutions of stress in the protected layer during protective layer mining were systematically explored through a combination of similar physical simulation experiments and PFC(Particle Flow Code)numerical simulations.In addition,the permeability of the protected layer was also analyzed with the aid of RFPA(Realistic Failure Process Analysis)numerical simulation software.The results disclose that after pressure relief mining,tensile transverse fractures are formed in the upper long-distance protected layer,which serve as transverse gas seepage channels for pressure relief.Under the influence of mining,overburden fractures start to extend in different layers,and they develop in a“trapezoidal”shape.The stress change curve of the protected layer changes from a“V”shape to a“U”shape.In addition,the protection boundary of the protected layer is staggered for about 10-20 m in the direction of the goaf of the protection layer,entering a stable pressure relief and dilatancy area.The permeability improves significantly,and a strong“pressure relief and permeability enhancement”effect is achieved.The corresponding time stage is the optimal“time window”for pressure relief gas extraction.

关 键 词：上向远距离 被保护煤层 PFC 横向裂隙 时间窗口期 

分 类 号：TD325[矿业工程—矿井建设]