Mechanical Analysis of Large-span Tunnel Construction in Urban Seaside

A tunnel in urban seaside is designed as a two-way eight-lane with a span of nearly 20 meters. The stratum is a horizontal layered rock mass and a three-level surrounding rock. In order to achieve rapid construction of large-span tunnels, combined with engineering background, horizontal layered rocks. The constitutive calculation model of the body is optimized and analyzed, and the whole time and space analysis of the tunnel construction process is carried out. The results show that for the layered rock mass stratum, the tunnel surrounding rock stress field is also the displacement field and the plastic zone distribution, and the transversely isotropic medium model is adopted. The root can fully reflect the engineering characteristics of the horizontal layered rock mass; The deformation of the tunnel surrounding rock after excavation shows that the horizontal layered rock mass is beneficial to the stability of the tunnel arch and the cavern; The settlement of the surrounding rock dome of the horizontal layered rock mass tunnel. The convergence deformation (6.0 mm) accounts for about 50% of the final deformation. The horizontal layered surrounding rock should actively control the deformation of the front of the face to enhance the stability of the cavity.