The ELI-Beamlines facility in the Czech Republic will offer to users versatile radiation sources in an unprecedented energy range. Laser-driven proton beams are expected to range between 50 MeV and 3 GeV. The number of particles delivered per laser shot is estimated to be 1010-10 12. Starting from analytical calculations, as well as from dedicated simulations, the main proton fields produced in the laser-matter interaction have been described and used to characterize the "source terms" in full simulations with the Monte Carlo code FLUKA in order to assess a proper shielding. We present the results of this study and the proposed solutions together with a cross-check analysis performed with the Monte Carlo code GEANT4.