基于内变量理论的岩土材料本构关系研究

Research on the constitutive relation of geomaterials based on the theory of internal variable

通过对基于经典弹塑性力学本构理论的岩土材料本构关系的分析,讨论了经典弹塑性力学本构理论存在的问题及局限性.根据现代连续介质力学热力力学原理和内变量理论,给出岩土材料本构关系中屈服函数的物理意义、屈服函数和耗散函数之间的关系;给出一种新的确定岩土材料弹塑性本构关系的方法.根据这一新方法推导了增量型本构关系的弹塑性矩阵,给出了塑性应变增量的表达式,证明了弹塑性耦合下的广义正交法则.说明了基于内变量理论的岩土材料弹塑性本构关系需要进一步探讨的问题.

The problems and limitations in constitutive theory of classical elastoplastic mechanics are discussed by analyzing constitutive models of geomaterials based on the constitutive theory. According to the principle of the modern continuum thermomechanics and the internal variable theory of the modern continuum mechanics, the physical meaning of the yield function in constitutive models of geomaterials and the relation between the yield function and the dissipation function are presented, and a new method to establish elastoplastic constitutive relation of geomaterials is proposed. With the method taken, the elastoplastic matrix of the incremental form of the constitutive equation is deduced, the increment equation of plastic strain is presented, and the generalized normality rule of elastoplastic coupling materials is proved. The problems, which are needed to be further studied, in establishing the elastoplastic constitutive relation of geomaterials by the internal variable theory, are also presented.