Modelling of internal fluid flow in cracks with embedded strong discontinuities

Abstract

This chapter presents a discrete approach for modelling failure of heterogeneous rock material with discrete crack propagation and internal fluid flow through the saturated porous medium, where the coupling conditions between the solid and fluid phase obey the Biot's porous media theory. Discrete cracks and localized failure mechanisms are provided through the concept of embedded discontinuity FEM. Furthermore, the basis for presented discrete 2D plane strain model representation of heterogeneous material consisting of material grains, is an assembly of Voronoi cells that are kept together by cohesive links in terms of Timoshenko beams. Embedded discontinuities are built in cohesive links thus providing the discontinuity propagation between the rock grains in mode I and mode II. The model can also take into account the fracture process zone with pre-existing microcracks coalescence prior to the localized failure. Several numerical simulations are given to illustrate presented discrete approach.