Civil and Environmental Engineering, Shiraz University , Fars, Iran
Due to the development of numerical modeling, tunnels' behavior before construction can be predicted by the designers. The compatibility of the numerical simulation with ground conditions results in more reliable predictions of the tunnels’ behavior in different environments. Several constitutive models for soil and rock have been proposed to simulate the ground characteristics; however, it is essential to utilize them appropriately. In this study, first, the convergence of a tunnel was modelled, and the results were verified by the actual convergence monitoring data. Then, a series of finite element simulations on a hypothetical TBM tunnel was conducted to demonstrate the difference in deformations, ground surface settlements, and stresses developed in the lining due to the tunnel excavation under seven constitutive models in rock mediums. Models were categorized into four groups rock specified, soil established and general.
Furthermore, parametric studies were conducted on specific gravity, Poisson’s ratio, and dilation angle. The results revealed that the prediction of different constitutive models could vastly influence numerical analysis results. The rock-specified models demonstrate more sensitivity to the variation of the parameters in rock medium than soil-established and general models. Also, a change in the specific gravity and Poisson’s ratio significantly influences surface settlement magnitude.