Micromechanical Model of Damage-seepage in Brittle Rocks

• Published in: Physical and Numerical Simulation of Geotechnical Engineering no. 26; p. 3
• Main Authors: Jianjun, Zhou, Jianfu, Shao
• Format: Journal Article
• Language: English
• Published: Brighton East St. Plum-Blossom Press Pty Ltd 01.03.2017
• Subjects: Brittleness; Computer simulation; Damage; Darcys law; Fluid flow; Laminar flow; Mathematical analysis; Mathematical models; Permeability; Rocks; Simulation analysis
• ISSN: 1838-3254; 2204-2040

Basing on the framework of thermodynamic theory and the micromechanics, this paper presents an anisotropic micromechanical damage model with taking a consideration of the peak strength of rock and confining pressure which can couples the variation of permeability. Taking the crack density function of rock as damage variable, the damage evolution is defined by the crack propagation criterion. The constitutive equation of cracked brittle rock is derived from the free enthalpy by micromechanical approach. It is assumed that the microcrack surfaces are rough, a normal aperture will be exhibit during the crack growth and sliding, which is the main reason why the rock permeability changes and is irreversible strain generates. According to Darcy's law for macroscopic fluid flow and laminar flow in microcracks, the permeability tensor can be derived for the cracked brittle rock; the micromechanical model of damage-seepage is established. The numerical simulation analysis shows that the proposed model agrees well with the experimental results.