Numerical Modelling Analysis of Radial Deformations Around a Circular Tunnel Excavated in Weak Rock Masses

Different causes such as technological developments, population growth, safety and comfort desired for travel have recently led to more tunnel opening. During the tunnel excavation, the deformation prediction of the rock mass around the tunnel is an important parameter for the support design. Researchers emphasize that the deformations behind of the advancing face in circular tunnels vary depending on distance to the face and proposed different equations that give longitudinal deformation profile (LDP) for circular underground openings. By using these equations, deformations around the tunnel can be estimated approximately. Numerical or physical modeling is required to predict deformations occurring in an underground opening. Numerical modeling method is more preferred because it is both easy and economical. In this study, a condition representing weak rock mass was determined and a circular opening which is 6,63 m in diameter in this rock mass condition was modelled for different depths (in situ stresses) based on the finite difference method. LDP curves for different depths using the deformation values obtained from models were created and the changes of depth-dependent deformation were investigated. These LDP curves obtained by modeling were compared with the equations in the literature