基于不可逆内变量热力学的岩石材料粘弹-粘塑性本构方程

发布时间：2018-10-15 09:29

【摘要】：岩石材料的粘弹性和粘塑性变形是与时间相关的能量耗散行为。在Rice不可逆内变量热力学框架下,引入两组内变量分别用来描述在粘弹性和粘塑性变形过程中材料的内部结构调整。通过给定比余能的具体形式和内变量的演化方程,推导出内变量粘弹-粘塑性本构方程。粘弹性本构方程具有普遍性,能涵盖Kelvin-Voigt和Poynting-Thomson在内的经典粘弹性模型的本构方程。并指出热力学力与应力呈线性关系是组合元件模型为线性模型的根本原因。粘塑性本构方程能较好地刻画岩石材料在粘塑性变形过程中的硬化现象。对模拟岩石的模型相似材料进行单轴加卸载蠕变试验,将蠕变过程中的粘弹性和粘塑性变形分离并根据试验数据对本构方程的材料参数进行辨识。试验数据和理论曲线对比结果表明该文提出的本构方程能很好地模拟材料的蠕变行为。该类型的本构方程能为岩石工程的长期稳定性的预测、评价以及加固分析提供基础。
[Abstract]:The viscoelastic and viscoplastic deformation of rock materials is a time dependent energy dissipation behavior. In the thermodynamic framework of Rice irreversible internal variables, two sets of internal variables are introduced to describe the internal structure adjustment of materials during viscoelastic and viscoplastic deformation respectively. By giving the specific form of specific complementary energy and the evolution equation of internal variables, the viscoelastic-viscoplastic constitutive equation of internal variables is derived. Viscoelastic constitutive equations are universal and can cover the constitutive equations of classical viscoelastic models including Kelvin-Voigt and Poynting-Thomson. It is pointed out that the linear relationship between thermodynamic force and stress is the fundamental reason why the combined element model is linear. The viscoplastic constitutive equation can describe the hardening of rock materials during viscoplastic deformation. Uniaxial loading and unloading creep tests were carried out to simulate the similar materials in rock model. The viscoelastic deformation and viscoplastic deformation during creep were separated and the material parameters of the constitutive equation were identified according to the experimental data. The comparison between the experimental data and the theoretical curves shows that the constitutive equation proposed in this paper can well simulate the creep behavior of the material. This kind of constitutive equation can provide the basis for the prediction, evaluation and reinforcement analysis of the long-term stability of rock engineering.
【作者单位】：清华大学水沙科学与水利水电工程国家重点实验室;
【基金】：国家自然科学基金项目(11172150,51279086) 水沙科学与水利水电工程国家重点实验室课题项目(2013-KY-2) 教育部新世纪优秀人才支持计划项目(NCET-13-0323)
【分类号】：TU45

【参考文献】