岩石的塑性、损伤及其本构表述

在工程条件下(常温、中低围压),岩石塑性变形和损伤变量的微观机制都是岩石构元中微裂纹的萌生和发育,因而塑性变形与损伤在岩石材料中应是同时出现的,它们的演化规律应是相互耦合的。在此基础上本文建立了岩石材料弹塑性损伤本构模型的理论框架。在这个框架中,由于损伤的出现,塑性变形率与屈服面是非正交的,而最后得到的本构矩阵具有对称性。非正交性与通常的实验资料一致。本构矩阵的对称性对数值分析和理论研究都是至关重要的。

ON ROCK PLASTICITY,DAMAGE AND THEIR CONSTITUTIVE FORMULATION

Under engineering conditions (i.e. the normal temperature and the middling or lower confining pressure), the microscopic mechanism of both plastic strain and damage variable in rock are the birth and the growth of the microfracture in a rock cell body. Thus the plasticity and damage shall appear at the same time and their evolution laws shall be coupled each other. For the above reasons, this paper established a theoretical frame of the constitutive model for elastoplastic damage in rock materials. In the frame the plastic strain rate is non-normal to the loading surface due to damage, but the obtained constitutive matrix is sysmmetrical. The non-normality is consistent with experimental data and the sysmmetry of the matrix is extremly important in the numerical analysis and theoretical research.