摘要
为明确煤矿水力压裂切顶卸压过程中岩石水力裂隙的时空演化规律,研究采用离散元方法构建水力压裂裂隙扩展与颗粒运移耦合模型,系统分析裂隙数量及形态、颗粒运移特征、损伤区面积对水压、内聚力、孔隙率及杨氏模量的响应规律。结果表明:①水压增大促使裂隙从线性扩展向复杂网状或分支形态转变,为颗粒运移提供更多通道,进而扩大损伤区面积;但过高水压会引发压实效应,降低裂隙通道有效性并抑制损伤区扩展。②内聚力提升使裂隙扩展更趋规则,颗粒位移模式由无序转为有序;孔隙率影响裂隙扩展复杂性与颗粒位移幅度,中等孔隙率条件下颗粒位移范围与幅度最优;杨氏模量增大使裂隙扩展路径更集中,颗粒位移的方向性显著增强。③裂隙时间演化过程可划分为起裂阶段(无裂隙增长)、微裂纹扩展阶段(裂隙缓慢增长)及裂纹快速扩展阶段(裂隙稳定快速增长),且不同变量条件下的水力裂隙时间演化曲线均呈指数函数分布。研究成果可为煤矿顶板水力压裂切顶卸压工艺参数优化及卸压效果提升提供理论支撑。
To clarify the spatiotemporal evolution patterns of rock fissures during hydraulic fracturing for roof cutting and pressure relief in coal mines,a coupled model of hydraulic fissures propagation and particles migration was developed using discrete element method.We systematically analyzed the response patterns of fissures number and morphology,particles migration characteristics,and damage zone area to water pressure,cohesion,porosity,and Young modulus.The results show that:Firstly,increased water pressure promotes the transition of fissures from linear propagation to complex network or branching morphologies,providing more channels for particles migration and thereby expanding the damage zone area.However,excessively high water pressure induces a compaction effect,reducing the effectiveness of fracture channels and inhibiting damage zone expansion.Secondly,increased cohesion leads to more regular fissures propagation,shifting particles displacement patterns from disordered to ordered.Porosity affects the complexity of fissures propagation and the magnitude of particle displacement,with optimal particles displacement range and magnitude observed under medium porosity conditions.Increased Young modulus results in more concentrated fissures propagation paths and significantly enhanced directionality of particles displacement.Thirdly,the temporal evolution of fissures can be divided into an initiation stage(no fissure growth),a micro-crack propagation stage(slow fissures growth),and a rapid crack propagation stage(stable and rapid fissures growth).The temporal evolution curves of hydraulic fissures under different variable conditions all follow an exponential function distribution.The research findings provide theoretical support for optimizing process parameters and improving the effectiveness of hydraulic fracturing for roof cutting and pressure relief in coal mine roofs.
作者
武少国
王元杰
苏士杰
赵乾
刘宁
李岩
WU Shaoguo;WANG Yuanjie;SU Shijie;ZHAO Qian;LIU Ning;LI Yan(Uxin Banner Mengda Mining Industry Co.,Ltd.,Ordos 017300,China;CCTEG Coal Mining Research Institude Co.,Ltd.,Beijing 100013,China;Key Laboratory of National Mine Safety Supervision Bureau for Mine Roof Disaster Prevention and Control,Beijing 100013,China;Zhongtian Hechuang Energy Co.,Ltd.,Ordos 017300,China)
出处
《煤炭工程》
北大核心
2025年第10期68-77,共10页
Coal Engineering
基金
中煤集团重大科技专项(20211BY001)。
关键词
水力压裂
切顶卸压
离散元法
裂隙扩展
损伤区
颗粒运移
厚硬顶板
hydraulic fracturing
roof cutting and pressure relief
discrete element method
fissures propagation
damage area
particles migration
thick and hard roof
