A numerical model to assess the creep of shotcrete linings

The behaviour of sprayed concrete (SC) tunnel linings was analysed considering the secondary deformation effects over time. Considering the behaviour of SC support under the loads applied by the rock mass and the interaction between the lining and the rock mass, a detailed analysis of the stress and deformation was performed using the convergence–confinement method (CCM) and the hyperstatic reaction method (HRM). In order to develop a procedure for the correct design of a shotcrete lining, an analysis was required that combined the CCM and the HRM. To take into account the creep phenomenon, the Voigt–Kelvin model was used to model the shotcrete; this model employs two springs and a viscous damper to reproduce the actual behaviour physically. Some useful findings were obtained on the trend of the safety factors of shotcrete linings over time.