采动扰动条件下煤层底板隔水层渗流效应及突水机理研究
发布时间：2018-07-14 21:48
【摘要】：本文运用弹塑性理论,并结合Griffith破坏准则对工作面端部屈服区破坏范围进行了分析,在此基础上运用滑移线场理论建立底板塑性区破坏力学模型,给出了底板最大破坏深度及其塑性区分布范围的理论求解方法,并分析了底板最大破坏深度与其影响因素的关系。运用材料力学理论将底板隔水层简化为弹性梁,考虑岩体损伤区内部孔隙压力的影响,运用损伤力学进行了理论分析,并给出了临界损伤变量Dc的计算公式。在此基础上,运用断裂力学建立断裂力学模型,并给出了采场隔水层承压水导升裂纹端部应力集中系数的计算公式。最后,确定出煤层底板有效隔水层厚度。运用断裂力学理论中优势裂纹角建立了采场裂隙岩体优势角应力-渗透性耦合力学模型,确定了原岩应力状态下岩体中裂隙分布的角度。在此基础上结合采场断裂力学模型,推导建立了采场平面应力状态下渗透系数方程,分析了采场附近岩体的渗透系数及其影响因素的关系。 结合双柳煤矿地质资料,运用FLAC3D数值模拟软件,模拟了工作面不同推进度、承压含水层不同岩性的情况,并对采场岩体的塑性区分布规律、工作面沿走向、倾向及底板深度方向的应力场分布特征,底板的位移特征进行了分析。模拟了煤层工作面不同宽度情况,对煤层底板应力场分布特征进行了分析。
[Abstract]:In this paper, the elastic-plastic theory and Griffith failure criterion are used to analyze the failure range of the yield zone at the end of the working face. On the basis of the analysis, the failure force model of the plastic zone of the bottom plate is established by using the slip line field theory. The theoretical solution method of the maximum failure depth and the distribution range of the plastic zone of the bottom plate is given, and the relationship between the maximum failure depth of the bottom plate and its influencing factors is analyzed. Based on the theory of material mechanics, this paper simplifies the bottom layer as elastic beam, considers the influence of internal pore pressure in rock mass damage zone, and makes theoretical analysis by using damage mechanics, and gives the calculation formula of critical damage variable DC. On the basis of this, the fracture mechanics model is established by using fracture mechanics, and the formula of stress concentration factor at the crack end of confined water conductance lift in water-proof layer of stope is given. Finally, the thickness of effective water insulation layer of coal seam floor is determined. Using the dominant crack angle in fracture mechanics theory, a mechanical model of stress-permeability coupling of fractured rock mass in stope is established, and the angle of fracture distribution in rock mass under the condition of original rock stress is determined. Based on the fracture mechanics model of stope, the equation of permeability coefficient under plane stress of stope is derived, and the relationship between permeability coefficient and influencing factors of rock mass near stope is analyzed. Combined with the geological data of Shuangliu Coal Mine, using FLAC3D numerical simulation software, this paper simulates the different advance degree of working face, different lithology of confined aquifer, and the distribution law of plastic zone of rock mass in stope, and the working face along the direction. The distribution characteristics of the stress field in the depth direction of the bottom plate and the displacement characteristics of the bottom plate are analyzed. The distribution characteristics of stress field in coal seam floor are analyzed by simulating the different width of coal seam face.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD74
本文编号：2123058
[Abstract]:In this paper, the elastic-plastic theory and Griffith failure criterion are used to analyze the failure range of the yield zone at the end of the working face. On the basis of the analysis, the failure force model of the plastic zone of the bottom plate is established by using the slip line field theory. The theoretical solution method of the maximum failure depth and the distribution range of the plastic zone of the bottom plate is given, and the relationship between the maximum failure depth of the bottom plate and its influencing factors is analyzed. Based on the theory of material mechanics, this paper simplifies the bottom layer as elastic beam, considers the influence of internal pore pressure in rock mass damage zone, and makes theoretical analysis by using damage mechanics, and gives the calculation formula of critical damage variable DC. On the basis of this, the fracture mechanics model is established by using fracture mechanics, and the formula of stress concentration factor at the crack end of confined water conductance lift in water-proof layer of stope is given. Finally, the thickness of effective water insulation layer of coal seam floor is determined. Using the dominant crack angle in fracture mechanics theory, a mechanical model of stress-permeability coupling of fractured rock mass in stope is established, and the angle of fracture distribution in rock mass under the condition of original rock stress is determined. Based on the fracture mechanics model of stope, the equation of permeability coefficient under plane stress of stope is derived, and the relationship between permeability coefficient and influencing factors of rock mass near stope is analyzed. Combined with the geological data of Shuangliu Coal Mine, using FLAC3D numerical simulation software, this paper simulates the different advance degree of working face, different lithology of confined aquifer, and the distribution law of plastic zone of rock mass in stope, and the working face along the direction. The distribution characteristics of the stress field in the depth direction of the bottom plate and the displacement characteristics of the bottom plate are analyzed. The distribution characteristics of stress field in coal seam floor are analyzed by simulating the different width of coal seam face.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD74
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