The propagation and bifurcation of fractures in fluid-filled porous media depends on the likewise inter-related flow in the pore space and on the mechanical displacement field in the solid matrix. Assuming that fractures cannot be homogenised but persist on a continuum-mechanical scale as sharp time-dependent interfaces, a discrete fracture-network approach is developed. The final task of the project is the construction of a multi-scale model that serves as the basis for numerical simu-lations by a moving mesh ansatz. In particular, the new approach accounts for the dynamical evolution of fractures and allows to integrate arbitrary flow processes within the fractures.