基于微观力学特性的脆性岩石变形过程模拟

Deformation simulation of brittle rock based on micromechanical properties

为了建立能够描述岩石宏观变形及其组成部分的变形模拟方法,考虑微缺陷的不均匀性对岩石宏观变形产生的影响,将岩石视为由空隙部分材料和骨架部分材料两部分组成。首先,基于岩石各组成部分材料变形分析,利用真应变描述方法及非线性变形的特点建立空隙部分材料的变形力学分析方法,同时,引入统计损伤以及固体力学理论建立骨架部分材料的变形力学分析方法。然后,通过岩石及其组成部分的变形力学分析建立岩石宏观变形力学分析方法,从而获得能够模拟岩石变形破坏全过程的统计损伤本构模型,并给出了模型参数的确定方法。最后,将文中模型与既有模型的理论曲线与试验曲线进行了对比分析,且基于文中模型对岩石及其组成部分变形进行了讨论。研究结果表明:文中模型不仅能反映既有模型所描述的主要变形特征,还能克服其难以较好地反映初期宏观变形非线性的不足;同时,该模型还能描述岩石组成部分的变形过程,不仅揭示了岩石宏观变形与其组成部分变形之间的关系,也揭示了空隙部分材料变形是引起岩石宏观变形非线性的根本原因。表明本文模型与方法具有一定的合理性与优越性。

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.