含瓦斯煤岩固气耦合动态模型与数值模拟研究
Solid-gas coupling dynamic model and numerical simulation of coal containing gas
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摘要: 首先在多孔介质的有效应力原理中引入瓦斯吸附的膨胀应力,推导出了适用于含瓦斯煤岩的有效应力计算公式。通过分析含瓦斯煤岩的孔隙度和渗透率在不同变形阶段的变化特点,在前人的研究成果基础上,建立了含瓦斯煤岩的孔隙度和渗透率的动态模型。假设含瓦斯煤岩是一种各向同性的弹塑性材料,同时考虑瓦斯吸附的影响,得出了含瓦斯煤岩的应力场方程和渗流场方程,建立了能描述固气耦合情况下煤岩骨架可变形性和瓦斯气体可压缩性的含瓦斯煤岩的固气耦合模型。最后通过给定模型的定解条件和相关参数,利用有限元方法建立了相关的数值计算模型,并得出了含瓦斯煤岩固气耦合模型的数值解。研究成果对进一步充实和完善含瓦斯煤岩固气耦合理论有一定意义。Abstract: An effective stress calculation formula for coal containing gas is proposed coupling with the swelling stress of gas adsorption in the effective stress principle for porous media.Considering the variation of the porosity and permeability of coal containing gas at differential deformation stages,a dynamic model for porosity and permeability is developed based on the previous research results.Furthermore,taking coal containing gas as a kind of isotropic elastoplastic material and taking into account the effect of gas adsorption,the stress and seepage equations are derived and,the solid-gas coupling model for coal containing gas is constructed,which is appropriate to describe the skeleton deformability of coal containing gas and the compressibility of gas under the solid-gas interaction condition.In addition,the numerical simulation model is built by using the finite element method,and the numerical solution of the model for a special loading case is given in term of the constraint conditions and corresponding parameters.The research results maybe have a meaning for further enriching and improving solid-gas coupling theories for coal containing gas.