A refined micromechanical damage-friction model with strength prediction for rock-like materials under compression

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:60-61

Article

Zhu, Q. Z.^1,2  Shao, J. F.^1,3 

[1] Hohai Univ, Inst Geotech Engn, Res Grp 2MS2E, Nanjing 210098, Jiangsu, Peoples R China

[2] Univ Paris Est, CNRS UMR8208, MSME, Marne La Vallee, France

[3] Univ Lille, CNRS UMR8107, LML, Villeneuve Dascq, France

关键词: Micromechanics;    Induced anisotropies;    Damage-friction coupling;    Back stress hardening/softening;    Brittle rocks;    Beishan granite;   

DOI  :  10.1016/j.ijsolstr.2015.02.005

来源: Elsevier

【 摘 要 】

Inelastic deformation and damage evolution at microdefects are two essential nonlinear mechanisms that govern macroscopic mechanical behaviors of quasi-brittle solids. The present paper deals in a unified framework with two dissipative processes in microcracks: inelastic deformation due to frictional sliding and damage by crack growth, usually arising and strongly coupled in cohesive materials under compression. Contributions by this work are threefold: (i) based on the Mod-Tanaka method, the free enthalpy of the representative elementary volume composed of a matrix phase and randomly oriented and distributed penny-shaped microcracks is determined for the general case of multiple crack families. The constitutive formulations are now presented in an elegant manner by using two orientation-dependent tensorial operators; (ii) the friction criterion is formulated in terms of the local stress applied onto microcracks. This local stress contains a back stress term that allows unified modeling of material hardening/softening behavior: friction-induced hardening is attributed to the cumulation of frictional shearing while damage-related softening is induced by crack growth and coalescence; (iii) originally, strength prediction is achieved through damage-friction coupling analyses. In that process, a basic feature of the damage resistance is revealed, leading to a novel damage criterion suitable for describing and modeling nonlinear mechanical behavior of quasi-brittle materials. Moreover, trans-scale relationship between the parameters in the local criteria and experimental data from laboratory tests is set up, which is always appealing in multiscale modeling. As a first phase of validation, the refined micromechanical model is finally applied to simulate laboratory tests on a granite under triaxial compression. (C) 2015 Elsevier Ltd. All rights reserved.

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