Abstract: With the development of urbanization, the environmental conditions of building construction are becoming more and more complex. For the construction of deep excavation adjacent to the subway tunnel, the impact of deep excavation and the unloading of the adjacent subway tunnel should be focus on. Therefore, the supporting structure type and the construction method of deep excavation are more stringent than the traditional methods. This paper presents an ultra-deep excavation project adjacent to a subway tunnel in China. The comprehensive deformation control approach for the ultra-deep excavation adjacent to a subway tunnel is proposed. The approach includes the strengthening of the subway side isolation pile, the bedrock grouting at the bottom of the excavation and the utilization of servo control for the supporting system. The effect of the comprehensive deformation control in the project is evaluated based on the deformation field monitoring of the adjacent subway tunnel and excavation supporting structure. The results show that the comprehensive deformation control for the construction of ultra-deep excavation can effectively control the deformation of the subway tunnel structure while improving the safety of the retaining structure and ensure the operation safety of the subway tunnel. The relevant conclusions can provide reference for similar projects.

Key words: Subway Tunnel, Ultra-Deep Excavation, Deformation Control, Isolation Piles, Servo System, Bedrock Grouting