Computational modelling of crack-induced permeability evolution in granite with dilatant cracks

A computational homogenisation technique is used to investigate the role of fine-scale dilatancy on the stress-induced permeability evolution in a granitic material. A representative volume element incorporating the heterogeneous fabric of the material is combined with a fine-scale interfacial decohesion model to account for microcracking. A material model that incorporates dilatancy is used to assess the influence of dilatant processes at the fine scale on the averaged mechanical behaviour and on permeability evolution, based on the evolving opening of microcracks. The influence of the stress states on the evolution of the spatially averaged permeability obtained from simulations is examined and compared with experimental results available in the literature. It is shown that the dilatancy-dependent permeability evolution can be successfully modelled by the averaging approach.