13th International Conference on Fracture June 16–21, 2013, Beijing, China -10- Figure 7. Local volumetric strain distribution inside the RVE at a deviatoric stress of 350 MPa 6. Concluding remarks Based on the results presented, XFEM discretisation techniques can be efficiently combined with the proposed RVE generation approach to investigate the permeability and mechanical properties of heterogeneous geomaterials. From a fluid transport perspective, this modelling tool could be used in order to identify microstructural features responsible for average (fixed) permeability properties of rocks, in combination with kridging type approaches combined with surface permeability experimental tests [6]. With respect to stress induced permeability evolution, a moderate increase of permeability was obtained as a result of local plastic degradation. Complementary investigations should be performed to analyse the confinement dependency of the permeability evolution, as well as to compare quantitatively such computational results with experimental data. Further developments could incorporate cracking in addition to the plastic dissipation mechanisms contributing to the local permeability evolutions, as well as more advanced plasticity formulations. Acknowledgements The first author gratefully acknowledges F.R.S-FNRS Belgium for funding through the FRIA grant 5.0.011.12.F. The Marie Curie International Outgoing fellowship supporting the MULTIROCK project and funded by EU is also acknowledged by the third and last authors. References [1] T.J. Massart, A.P.S. Selvadurai, Stress-induced permeability evolution in a quasi-brittle geomaterial, J. Geophys. Res., 117 (2012) B07207. [2] I. Ozdemir I, W.A.M. Brekelmans, M.G.D. Geers. Computational homogenization for heat conduction in heterogeneous solids. Int. J. Numer. Meth. Engng. 2008; 73:185-204. [3] B. Sonon, B. François, T.J. Massart, A unified level set based methodology for fast generation of complex microstructural multi-phase RVEs, Comp. Meth. Appl. Mech. Engng., 223-224 (2012) 103-122. [4] B. Sonon, B. François, T.J. Massart, Generation of complex three-dimensional RVEs for computational homogenisation, In preparation, 2013. [5] N. Moes, M. Cloirec, P. Cartraud, J.F. Remacle, A computational approach to handle complex microstructure geometries, Comp. Meth. Appl. Mech. Engng. (2003), 192(28-30):3163-3177. [6] A.P.S. Selvadurai, P.A. Selvadurai, Surface permeability tests: experiments and modelling for estimating effective permeability, Proc. R. Soc. A (2010), 466:2819-2846
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