Numerical simulation of the deformation control of surrounding rock of large-span tunnel in soft rock under different excavation methods

摘要

The deformation control of surrounding rock of large-span tunnel in soft rock has become a great concern. Combined with an engineering practice, two methods including benching tunnel method and intermediate wall method have been studied and numerically simulated using the ANSYS software. The stress and deformation of surrounding rock caused by the tunnel excavation under different construction methods have also been analyzed, which hopefully, will provide a better insight in construction of tunnel. It is found that as a result of the existence of median septum and which supports the upper load from the soil to a certain extent and the vault vertical displacement is reduced. As for benching tunneling method, the vertical displacement is larger. Accordingly, when CD method is adopted, the surrounding rock stress is minor.