Research and Design Optimization of Canceling Setting Invert in Road Tunnel

Use FLAC 3D finite difference software for numerical simulation and static calculation of the different models. Study the deformation and forces condition of different model during the process of excavation. The results show that setting invert of highway tunnel in Ⅳ1-grade rock section can improve the stress state of the supporting structure and reduce the surrounding rock deformation effectively. At the same time, the flat bottom tunnel applying C25 concrete and grouting bolts could improve the integrity of surrounding rock below the tunnel sidewall. It is can be considered to cancel the setting of invert to achieve the purpose of simplifying the construction and design.