基于能量效应的覆岩破断与瓦斯运移耦合动力学机理研究

It has important theoretical significance and engineering value for improvement of the theory of multi-physical coupling with coal seam mining and discriminate method of gas storage and transport zone in fissure of overburden strata that is studied on energy coupling mechanism of mining overburden strata breakage and gas migration. Constitutive model of complete stress-strain with energy effect is constructed by rock mechanics, percolation flow mechanics, adsorption/desorption and energy dissipation. Similitude rule of rock breakage and gas migration with energy effect is obtained by above constitutive model and theories. Research on properties of mechanic, permeability and energy dissipation of samples with different material ratio is used by independently developed true triaxial “stress-permeability-energy” comprehensive experiment table and adsorption/desorption device. One simulation material that is suitable for carrying out three-dimensional “solid-gas –energy” coupling physical analog simulation experiment is obtained by the results of properties study. The law that is energy coupling of mining overburden strata fracture evolution and gas migration is gained by three-dimensional physical analog simulation experiment aim at typical high gassy mine. Based on above study results, dynamic model of mining overburden breakage and gas migration is established by used some related theoretical that is damage mechanics, percolation flow mechanics, adsorption/desorption and energy dissipation theory. Connection of main parameters of dynamic model is analyzed by numerical simulation method, meanwhile comparing the results between physical experiment and numerical simulation. Then the energy coupling dynamic mechanism of mining overburden strata breakage and gas migration is revealed.

研究采动覆岩破断与瓦斯运移过程的能量耦合机理对于完善煤层采动多物理场耦合理论及采动覆岩裂隙中瓦斯储运区判别方法具有重要的理论意义和工程价值。运用岩石力学、渗流力学、吸附解吸及能量耗散等理论，建立考虑能量效应的岩石全应力-应变本构模型，并推导出岩体破断与瓦斯运移的相似准则。再利用自主研发的真三轴“应力-渗流-能量”综合测试实验台及吸附解吸装置，对不同配比材料制作的试件开展力学、渗透、吸附解吸及能量耗散特性研究，获得适于开展三维“固-气-能量”耦合物理相似模拟实验的材料，针对典型高瓦斯矿井开展三维物理相似模拟实验，得到采动覆岩裂隙演化及瓦斯运移的能量耦合规律。运用损伤力学、渗流力学、吸附解吸及能量耗散等理论，建立考虑能量效应的采动覆岩破断与瓦斯运移动力学模型，同时利用数值模拟方法，分析模型主要参数之间的关系，将结果与实验结果进行对比，揭示采动覆岩破断与卸压瓦斯运移的能量耦合动力学机理。

采动引起的覆岩破断与卸压瓦斯运移之间的规律已有很多的研究成果，但其二者之间的耦合关系仍需进一步研究。针对这一问题，项目基于能量耗散原理，结合理论分析、实验室实验、物理模拟实验等手段，对采动覆岩破断与卸压瓦斯运移之间的耦合关系开展进了系统性的研究。相关研究成果发表学术论文28篇（SCI、EI、CSCD收录23篇），培养硕士7人，参加国内外学术会议9次，授权国家发明专利6项、实用新型专利6项、软件著作权3项，指导1个煤矿开展了瓦斯抽采设计。主要研究成果有：.（1）获得岩石在全应力应变过程中所经历的5个阶段均伴随着能量的积累与释放，在此基础上，结合弹性力学、塑性力学、Helmholtz自由能理论及Clausius-Duhem不等式等得出基于能量耗散原理的岩石全应力应变损伤力学模型及相似准则。.（2）确定合理的骨料与胶结剂组合，利用不同组合的材料在保证抗压强度相同的基础上，对所制作的试件进行抗拉强度、脆性参数、渗透性及吸附特性测试，实验结果表明在抗拉强度、脆性参数、渗透性及吸附性能方面所选材料均能满足模拟岩石的要求。.（3）获得水泥沙子质量比、淀粉含量与试件抗压强度之间的计算模型，同时也得到水泥沙子质量比、淀粉含量、落锤次数及骨料粒径与渗流速度之间的计算模型，确定制作三维“固-气”耦合物理相似模拟实验模型时各种材料用量及制作工艺的定量关系。.（4）得到覆岩下沉量、破断裂隙贯通度、离层裂隙离层率及采动覆岩破断能量释放沿工作面推进方向的分布形态，同时得到采空区横三区的范围及瓦斯运移的基本规律。.（5）建立了基于能量耗散原理的采动裂隙椭抛带卸压瓦斯渗流-升浮-扩散与能量耗散之间耦合的综合控制模型，通过对模型各参数的分析，得到采动过程中覆岩裂隙破断与瓦斯渗流-升浮-扩散之间的能量耦合机理，为煤与瓦斯共采理论体系提供了理论支撑。