Abstract: The deep excavation construction can cause deformation and accessory stress near existing tunnels, affecting the safe operation of tunnels. This article is based on the deep excavation engineering and establishes excavation models for two working conditions by using a numerical software. The influence of the distance between the excavation and the tunnel on the vertical and horizontal displacement of the existing tunnel is analyzed, and the safe distance between the excavation and the tunnel is estimated. In response to the difficulty of existing subway tunnels passing through deep excavations on both sides, a zoning and block based asymmetric excavation scheme is proposed, following the principle of zoning and block division. Through the onsite monitoring, the deformation curves of the existing tunnel’s vertical deformation and clearance convergence along the tunnel axis were obtained after the deep excavation was completed. Research has shown that as the distance between the deep excavation and the tunnel increases, both the vertical and horizontal displacements of tunnels on both sides decrease to varying degrees, especially during the process of increasing the distance from 10m to 12m. The safe distance between the deep excavation and the tunnel in this project is 12m; The impact of the excavation construction on the deformation of curved tunnels is greater than that of the straight tunnels. The research content of this article can provide a reference for similar projects.

Key words: Deep Excavation on Both Sides, Existing Tunnels, Numerical Simulation, On Site Monitoring, Deformation Analysis