Coupling between anisotropic damage and permeability variation in brittle rocks

Jian Fu Shao, H. Zhou, Kam Tim Chau

Research output: Journal article publicationJournal articleAcademic researchpeer-review

140 Citations (Scopus)

Abstract

In this paper, a coupled constitutive model is proposed for anisotropic damage and permeability variation in brittle rocks under deviatoric compressive stresses. The formulation of the model is based on experimental evidences and main physical mechanisms involved in the scale of microcracks are taken into account. The proposed model is expressed in the macroscopic framework and can be easily implemented for engineering application. The macroscopic free enthalpy of cracked solid is first determined by approximating crack distribution by a second-order damaged tensor. The effective elastic properties of damaged material are then derived from the free enthalpy function. The damage evolution is related to the crack growth in multiple orientations. A pragmatic approach inspired from fracture mechanics is used for the formulation of the crack propagation criterion. Compressive stress induced crack opening is taken into account and leads to macroscopic volumetric dilatancy and permeability variation. The overall permeability tensor of cracked material is determined using a micro-macro averaging procedure. Darcy's law is used for fluid flow at the macroscopic scale whereas laminar flow is assumed at the microcrack scale. Hydraulic connectivity of cracks increases with crack growth. The proposed model is applied to the Lac du Bonnet granite. Generally, good agreement is observed between numerical simulations and experimental data.
Original languageEnglish
Pages (from-to)1231-1247
Number of pages17
JournalInternational Journal for Numerical and Analytical Methods in Geomechanics
Volume29
Issue number12
DOIs
Publication statusPublished - 1 Oct 2005

Keywords

  • Brittle rocks
  • Damage models
  • Granite
  • Induced anisotropy
  • Microcracks
  • Permeability change

ASJC Scopus subject areas

  • Computational Mechanics
  • Materials Science(all)
  • Geotechnical Engineering and Engineering Geology
  • Mechanics of Materials

Cite this