Abstract: The aim of this paper is to develop a method for simulating the macroscopic deformation of rock and the deformation of each component. Rocks can be regarded as the composition of voids part material and skeleton part material by considering the effect of heterogeneity of microdefects on macroscopic deformation of rock. Firstly, a deformation analysis method for voids part material is proposed by using the method of true strain description and the characteristic of nonlinear deformation. Meanwhile, on the basis of statistical damage theory and solid mechanics theory, a deformation analysis method for skeleton part material is developed. Then, a macroscopic deformation analysis method is established by analyzing the deformation process of rock and its components, which is used to obtain a statistical damage constitutive model for simulating the whole process of deformation and failure of rock. Moreover, the methods for determining the parameters of the constitute model are also given. Finally, experimental data and theoretical results of the proposed model and existing models are compared and analyzed. The deformation processes of rock and its components materials are further discussed. The current study indicates that the proposed model can not only reflect the main deformation characteristics of rock, but also overcome the difficulty of reflecting the characteristics of rock nonlinear deformation during initial voids compaction stage. In addition, the proposed model can be used to describe the deformation characteristics of components materials, and to reveal the relationship between macroscopic deformation of rock and the deformation of each component material. It has been shown that the deformation of voids part material is the fundamental reason for rock nonlinear deformation.

Key words: rock, microdefects, nonlinearity, components, constitutive model