Parametric analysis of tunnel behavior in jointed rock

Jointed rock masses are often encountered during underground excavation. Many failures of underground openings, during excavation and in operation, are reported closely related to joints. This paper investigates the impact of three basic factors affecting the tunnel behavior in jointed rock; rock joints density, joints orientation and tunnel depth, respectively. A parametric study has been also conducted using two elastoplastic numerical models; the four-parameters Ottosen plasticity model and Mohr–Coulomb criterion, for concrete lining and rock mass, respectively. Eleven tunnel cases have been analyzed with different combinations of tunnel depth, joint orientation and joint density. The tunnel behavior has been evaluated by investigating; the resulted deformations, evolution of plastic regions and induced stresses in the concrete lining and the surrounding jointed rock. The obtained numerical results have been analyzed and discussed displaying the importance to consider these factors affecting the behavior of tunnels constructed in jointed rock.