Influences of excavation on adjacent existing metro tunnels: a review

The excavation-induced unloading will disturb the surrounding rock and soil mass, and then have a negative effect on the adjacent existing metro tunnels. For the two positions of s tunnel outside and below the foundation pit, the state-of-the-art achievements are summarized from the following four aspects: the influence mechanism of deep excavation on the existing tunnels, the influenced zone for tunnel deformation induced by excavation, the prediction methods for tunnel deformation and the control methods for tunnel deformation. Finally, the main problems to be solved and the key research directions in the future are discussed.