摘要
针对浅埋坚硬顶板工作面在回采过程中顶板难以及时垮落的问题,以陕北地区某矿517工作面为研究背景,设计了定向长钻孔分段水力压裂方案,并基于微震和现场实测数据对卸压效果进行评价。研究结果表明:在压裂施工过程中微震事件数显著增多,同时出现大能量微震事件,压裂最大破裂压力约为20.6 MPa,各压裂段注水量约为45 m3/h,压裂曲线出现压降现象,说明水力压裂导致钻孔内部出现裂缝并诱发了大量的顶板破裂现象,且压裂施工结束后顶板破裂仍受水力压裂影响;回采过程中煤柱浅部基点应力明显大于深部,煤柱帮部锚杆受力明显大于顶板及实体煤帮部锚杆,顶板离层量基本保持不变。水力压裂有效弱化了坚硬顶板的完整程度,减小了侧向支承压力对煤柱的影响,切断了应力传递路径,优化了煤柱的受力环境,有效缓解了巷道变形,保证了综采工作面的安全回采。
To address the challenge of timely roof collapse during the working faces mining of shallow coal seams under hard roofs,we took on the No.517 working face of a mine in northern Shaanxi as the background,and designed a staged hydraulic fracturing scheme using directional long boreholes,and the pressure relief effect was evaluated using microseismic and field measurement data.The results indicate a significant increase in microseismic events during fracturing,along with the occurrence of high-energy microseismic events.The maximum fracturing pressure reached approximately 20.6 MPa,with a water injection rate of around 45 m 3/h per fracturing section.The observed pressure drop in the fracturing curve suggests that hydraulic fracturing induces borehole fractures and a significant number of roof fractures,with the roof remaining influenced by fracturing even after construction.During mining,the stress at the base point in the shallow part of the coal pillar is significantly greater than in the deeper part.Similarly,the stress on bolts in the coal pillar side is markedly higher than on the roof and solid coal side.Meanwhile,the degree of roof strata separation remains essentially unchanged.Hydraulic fracturing effectively weakens the integrity of the hard roof,reduces lateral bearing pressure on the coal pillar,disrupts stress transmission paths,optimizes the stress environment,alleviates roadway deformation,and ensures the safe mining of the fully mechanized face.The research findings provide valuable insights for managing roof disasters in similar working faces.
作者
任建喜
闫伟
徐宝军
苗彦平
焦金照
孙成伟
王珂
REN Jianxi;YAN Wei;XU Baojun;MIAO Yanping;JIAO Jinzhao;SUN Chengwei;WANG Ke(School of Civil and Architecture Engineering,Xi’an University of Science and Technology College,Xi’an 710054,China;Shaanxi Coal Group Shenmu Hongliulin Mining Co.,Ltd.,Yulin 719300,China)
出处
《煤炭工程》
北大核心
2025年第9期49-57,共9页
Coal Engineering
基金
陕西省自然科学基础研究计划联合基金项目(2019JLP-01)。
关键词
浅埋煤层
坚硬顶板
水力压裂
微震
定向钻孔
shallow coal seam
hard roof
hydraulic fracturing
microseism
directional drilling
作者简介
任建喜(1968—),男,陕西西安人,博士,教授,主要从事岩土损伤力学、岩土力学数值方法、城市地铁车站与区间隧道变形规律和复杂条件下煤矿巷道支护技术研究工作,E-mail:renjianxi1968@163.com。
