Micromechanics Approach to the Effective Permeability of a Jointed Rock

Resumo

The use of macroscopic models in numerical approaches for studying subsurface flow has become
common practice in hydrogeology and petroleum engineering since the late 1960’s. Particularly in rock masses,
where the presence of joints constitutes a key weak point along which the mechanical, physical and hydraulic
properties of rock matrix degrade, the presence of discontinuities, at different scales, represent a fundamental
component of transport of fluid or contaminants through rock masses. However, one of the major questions that
still poses a problem is what parameters to introduce into the models. From a transport properties viewpoint, joints
within rock masses represent preferential channels for fluid flow and, as such, may be contributors to rapid transport
of fluid and contaminants through rock masses, particularly when the permeability of the rock matrix is low. This
article aims to present a micromechanical approach to the derivation of jointed rock permeability. Several examples
are present for different numbers of joint sets crosscutting rock masses, showing the flow anisotropy introduced by
their presence.