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A Numerical Investigation on Time-Dependent Failure of Tunnels Based on the Long-Term Strength Characteristics of Rocks

How to establish the proper rheological model to describe and simulate the relationship between rock mechanic characteristics and time is one of the difficulties in the tunnel long-term stability analysis. In this paper, a numerical model to replicate the time-dependent deformation of rock mass was presented. In the model, the time-dependent deformation is described in terms of degradation of intrinsic physical and mechanical properties of rock and accumulation of mesoscopic damage inside the rock. Based on the model, uniaxial numerical experimentation and tunnel numerical model test are numerically constructed and investigated respectively. The model well reflects the initial creep, steady creep of rock and accelerated creep, which preliminary prove the validity of the proposed model. The results of the tunnel numerical model test show that the displacement curves from the numerical simulation were generally consistent with those from physical model tests. Furthermore, the macroscopic failure modes and local mesoscopic damage evolution of the tunnels were simulated.