Formulation of mixed-hybrid FE model of flow in fractured porous medium

We encounter many problems, within which we try to model the groundwater flow in the disrupted rock massifs using numerical models. So-called "standard approaches" such as replacement by porous medium or double-porosity models of discrete stochastic fracture networks appear to have constraints and limitations, which make them unsuitable for the large-scale long-time hydrogeological calculations. This article presents the mathematical formulation of model based on a new approach to the modelling of groundwater flow, which combines the two above-mentioned approaches. The approach considers three substantial types of objects within a structure of modelled massif important for the groundwater flow small stochastic fractures, large deterministic fractures and lines of intersection of the large fractures. The systems of stochastic fractures are represented by blocks of porous medium with suitably set hydraulic conductivity. The large fractures are represented as polygons placed in 3D space and their intersections are represented by lines. Thus flow in 3D porous medium, flow in 2D and 1D fracture systems, and communication among these three systems are modelled together.