考虑体积塑性应变的岩石损伤本构模型研究

采用Eshelby等效夹杂方法建立岩石弹塑性损伤本构模型是一种有效方法,但相关文献目前还极少。在连续介质损伤力学框架内利用细观力学的Eshelby等效夹杂方法建立了考虑损伤相塑性体积变形的岩石的Helmholtz自由比能函数。利用连续介质损伤力学方法推导出了考虑损伤相塑性变形的岩石损伤本构关系,给出了损伤演化方程和塑性应变发展方程。并通过数值模拟证实该模型能够反映岩石体积塑性应变、损伤的变化规律和损伤部分不能承受拉应力等力学特性。

A DAMAGE CONSTITUTIVE MODEL FOR ROCK WITH PLASTIC VOLUME STRAIN

The Eshelby equivalent inclusion method is an effective method to establish the constitutive models for elastoplastic and damage rock. There have been only a few publications addressing the Eshelby equivalent inclusion method for establishment of the constitutive models until now. In this paper, a Helmholtz free energy function for damage rock with plastic volume strain is set up by the Eshelby equivalent inclusion method in the framework of continuum damage mechanics. A constitutive equation for damage rock with plastic volume strain is obtained from the Helmholtz free energy function with the theory of continuum damage mechanics. The corresponding damage evolvement equation and an evolvement equation of plastic volume strain are deduced. Numerical results show that the constitutive model can reflect the plastic volume strain affecting damage and damaged rock can not transfer tensile stress.