非均匀煤岩渗流-应力弹塑性耦合数学模型及数值模拟

利用Weibull分布模拟煤岩弹性模量和强度的非均匀性，结合煤岩弹塑性变形理论和瓦斯渗流理论，建立了非均匀煤岩渗流-应力弹塑性耦合数学模型，给出了该数学模型的有限元离散方程，开发了相应的数值计算程序Coupling Analysis。利用建立的模型模拟了辽宁某瓦斯抽放试井瓦斯抽放过程，结果表明，在瓦斯抽放过程中，有效应力变化诱发煤岩局部进入塑性状态，塑性区透气系数增加了约4.9倍，而弹性受压区的透气系数最大减小至22 %，计算实例的瓦斯压、煤岩有效应力和煤岩变形都呈现非对称性，但服从理论规律，表明采用Weibull分布能很好地模拟煤岩力学参数的非均匀性。

Seepage-stress elastoplastic coupling model of heterogeneous coal and numerical simulation

Weibull distribution is adopted to simulate the heterogeneity of Young’s modulus and strength of coal; and the seepage-stress elastoplastic coupling mathematical model of heterogeneous coal is presented based on elastoplastic theory of coal rock and the gas flow theory. Then the finite element discretized equation of the model is obtained; and the code (coupling analysis) is developed. In a case study, the gas flow process for a gas production well in Liaoning is analyzed with the model; and some conclusions are obtained. During the gas production well works, the change of the effective stress of coal causes coal plastic failure. In plastic failure region the permeability increases by 4.9 times than initial one; while the permeability in elastic region reduces to 22% because of effective stress increasing. The gas pressure, effective stress and deformation of coal in the case study all are asymmetrical, yet obey theoretical laws. It is proved that the Weibull distribution can simulate the heterogeneity of coal.