Long-term stability analysis of tunnel lining in weak rocks using data from tunnel construction
Time-dependent deformation of weak rocks has a significant effect on the stability of underground structures. Tunnel surrounding ground deformation in weak rocks may causes to gradual development of loading on the support system and threats the tunnel stability. In this research, the time-dependent behavior of the Shibli tunnel host rock was numerically simulated considering Burger-creep viscoplastic model (CVISC). Displacement based direct back analysis using univariate optimization algorithm were applied and properties of the CVISC model and initial stress ratio were estimated for the rock mass. Using back analysis results, creep behavior of the rock mass was predicted during tunnel service life. Simulation results show that thrust force, bending moment and the resulting axial stresses will remarkably increase at the spring line of the final lining with time, thus the tunnel inspection and rehabilitation are recommended.