A macro-mesoscopic constitutive model for porous and cracked rock under true triaxial conditions  

作　　者：Li Qian Zuguo Mo Jianhai Zhang Xianglin Xing Ru Zhang Tianzhi Yao Yunpeng Gao 

机构地区：[1]State Key Laboratory of Hydraulics and Mountain River Engineering,College of Water Resources and Hydropower,Sichuan University,Chengdu,610065,China [2]Power China Chengdu Engineering Corporation Limited,Chengdu,610072,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第8期3080-3098,共19页岩石力学与岩土工程学报（英文版）

基　　金：funding support from the National Natural Science Foundation of China(Grant No.U1965203);“Dynamic analysis method of complex rock underground engineering in the Hengduan Mountains”project(Grant No.P43419);the Sichuan University Postdoctoral Research Fund(Grant No.2023SCU12123).

摘　　要：The complex mechanical and damage mechanisms of rocks are intricately tied to their diverse mineral compositions and the formation of pores and cracks under external loads.Numerous rock tests reveal a complex interplay between the closure of porous defects and the propagation of induced cracks,presenting challenges in accurately representing their mechanical properties,especially under true triaxial stress conditions.This paper proposes a conceptualization of rock at the mesoscopic level as a two-phase composite,consisting of a bonded medium matrix and frictional medium inclusions.The bonded medium is characterized as a mesoscopic elastic material,encompassing various minerals surrounding porous defects.Its mechanical properties are determined using the mixed multi-inclusion method.Transformation of the bonded medium into the frictional medium occurs through crack extension,with its elastoplastic properties defined by the DruckerePrager yield criterion,accounting for hardening,softening,and extension.MorieTanaka and Eshelby’s equivalent inclusion methods are applied to the bonded and frictional media,respectively.The macroscopic mechanical properties of the rock are derived from these mesoscopic media.Consequently,a True Triaxial Macro-Mesoscopic(TTMM)constitutive model is developed.This model effectively captures the competitive effect and accurately describes the stress-deformation characteristics of granite.Utilizing the TTMM model,the strains resulting from porous defect closure and induced crack extension are differentiated,enabling quantitative determination of the associated damage evolution.

关 键 词：MICROMECHANICS Macroemesoscopic HOMOGENIZATION Constitutive model Competitive effect 

分 类 号：TU45[建筑科学—岩土工程]