受载含瓦斯煤渗流特性及其应用研究

发布时间：2018-08-14 10:10

【摘要】：瓦斯异常涌出和煤与瓦斯突出事故是在多场耦合作用下煤体失稳破坏而引发的动力灾害，而作为煤层中瓦斯流动难易程度指标的渗透率和煤层瓦斯多场耦合模型共同成为煤层内瓦斯运移规律研究中最重要也最基础的关键问题，本文通过自主搭建受载含瓦斯煤体渗流特性实验装置，，研究了不同孔隙压力、不同围压、不同有效应力和不同温度条件下煤样瓦斯渗透特性，在考虑吸附变形量、孔隙气体压缩量和温度膨胀变化量的基础上，建立了受载含瓦斯煤的孔隙率与有效应力之间的关系方程、渗透率与有效应力的关系方程及瓦斯在受载煤体中的非线性渗流方程。将原有有效应力理论与损伤力学的基本原理相结合，在考虑应力、孔隙压力和温度效应影响下把受载含瓦斯煤体的变形机制分为三种，根据煤体的应变量是有效应力σe的函数，建立了含瓦斯煤体的应力-应变的本构关系，结合渗透率与有效应力的关系方程，建立了渗透率的动态演化模型。并将受载含瓦斯煤体的应力-应变过程与动压巷道周围煤体的应力-应变过程相结合，视受载含瓦斯煤体为粘弹塑性软化介质，理论推导了巷道周围煤体塑性软化区和破碎区半径的计算公式，建立了考虑渗透率动态演化的巷道周围煤体瓦斯渗流方程及流固耦合模型。结合数值模拟的研究方法，分析了不同条件下巷道周围煤体不同区域应力分布及渗透率变化规律，通过现场实际验证，得出现场验证、理论分析和数值模拟结果基本相一致。
[Abstract]:Abnormal gas emission and coal and gas outburst accidents are dynamic disasters caused by instability and failure of coal body under multi-field coupling. As an index of the difficulty of gas flow in coal seam, permeability and multi-field coupling model of gas flow in coal seam are the most important and basic key issues in the study of gas migration in coal seam. In this paper, the seepage characteristics of coal samples under different pore pressures, different confining pressures, different effective stresses and different temperatures are studied by building an experimental apparatus for seepage characteristics of loaded gas-bearing coal bodies. The adsorption deformation is considered. On the basis of pore gas compression and temperature expansion change, the relationship equation between porosity and effective stress of loaded gas-bearing coal, the relation equation between permeability and effective stress, and the nonlinear seepage equation of gas in loaded coal body are established. Combining the original effective stress theory with the basic principle of damage mechanics, the deformation mechanism of loaded gas-bearing coal body is divided into three kinds under the influence of stress, pore pressure and temperature effect. According to the function of effective stress 蟽 e, the strain of coal body is the function of effective stress 蟽 e. The constitutive relation of stress-strain of gas-bearing coal is established, and the dynamic evolution model of permeability is established by combining the equation of permeability and effective stress. The stress-strain process of loaded gas-bearing coal is combined with the stress-strain process of coal around dynamic pressure roadway, and the loaded gas-bearing coal is regarded as viscoelastic-plastic softening medium. The formulas for calculating the radius of the ductile softening zone and the broken zone around the roadway are derived theoretically, and the seepage equation and fluid-solid coupling model of the coal body around the roadway considering the dynamic evolution of permeability are established. Combined with the research method of numerical simulation, the stress distribution and permeability change law of coal body around roadway under different conditions are analyzed. Through field verification, the field verification is obtained, and the theoretical analysis is basically consistent with the numerical simulation result.
【学位授予单位】：中国矿业大学（北京）
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TD712

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