Optimization Study on Maintenance Structure of Shaft in Shield Tunnel

There are many factors involved in the maintenance structure of shaft in shield tunnel, and the interaction between various factors is complicated. Combined with starting shaft construction of Xijiang River slurry shield tunnel, this paper analyzed the characteristics and applicability of common foundation maintenance structure, and proposed a composite support consists of diaphragm wall and bolt-shotcrete. A numerical simulation method was used to study the displacement regulation of soil surrounding the maintenance structure and ground settlement features under different excavation footage when using composite support. Construction results show that this composite support effectively ensure the safety of shaft construction.