基于内时理论的含瓦斯煤岩损伤本构模型研究

Endchronic damage constitutive model of coal containing gas

从内时理论出发,通过内蕴时间的重新构造,在Helmholtz自由能中引入损伤变量,利用连续介质不可逆热力学的基本原理推导出了含瓦斯煤岩的内时损伤本构方程,并给出了确定本构模型中各参数的方法。同时,对在三轴应力条件下所建立的本构方程进行了求解分析与试验验证。结果表明,该本构方程能很好地描述含瓦斯煤岩在损伤发生前后的变形特点,并能有效地反映含瓦斯煤岩的非线性和剪胀扩容等物理力学现象。

Starting from the endochronic theory, by rebuilding intrinsic time and introducing a damage variable into the Helmholtz free energy, a new set of endochronic damage constitutive equations of coal containing gas are deduced using the basic principles of the irreversible thermodynamics of continuum media; and what＇s more the method for getting parameters of the constitutive model is also presented. At the same time, solution analysis and experimental validation of the equations of coal containing gas under triaxial stress condition are performed. The results show that the endochronic damage constitutive equations can describe faithfully the properties of coal containing gas before and after damage and also can reflect effectively the nonlinear and shear expansion mechanical phenomena of coal containing gas.