A three-dimensional model of an underground excavation and comparison with in situ measurementsA three-dimensional model of an underground excavation and comparison with in situ measurements Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2015-11-052007enIn this paper we make the first attempt to construct a three-dimensional (3D) distinct element model (DEM) of an underground room with a central pillar in Dionysos marble deposit. This model can be employed in the future by the quarrymen to improve the design of the underground quarry. In order to decrease the effort and time of the simulations, the approach followed here is first to upscale intact rock properties to the size of the pillar considering also secondary joints, and next to model explicitly the major joint sets that transect the marble by virtue of a 3D DEM. The estimation of the effective marble properties is based on the concept of ‘damage’ as it is defined in damage mechanics theory, the phenomenon of the size effect of strength of intact rocks and the Rock Mass Rating (RMR) classification. Furthermore, a pre-processor has been written in C language for the efficient transfer of the large number of successive excavations around the central pillar to the 3D numerical model. Finally, the validity of this first series of numerical simulations, results and inherent assumptions are checked against in situ stress and deformation measurements inside the underground quarry.http://creativecommons.org/licenses/by/4.0/International Journal for Numerical and Analytical Methods in Geomechanics313411-433 Exadaktylos Georgios Εξαδακτυλος Γεωργιος Liolios Pantelis Λιολιος Παντελης Tsouvala Stavroula Μπαράκος Γεώργιος Barakos George John Wiley and Sons Dionysos marble Discontinuities Joints Room and pillar method Distinct element method Damage mechanics RMR Size effect