Abstract: Shenzhen Metro Dayun Hub Station is a transfer hub among Metro Lines 3, 14, 16, and Intercity Line 33. The underground part shall be constructed first to ensure the operation of the metro, and then the property part shall be constructed to form the landmark project of the integration of the Grand Transport Hub Station and City. In the development of underground space, there are some technical problems, such as the protection of operating station and viaduct, the construction of largediameter pile foundation with super clearance, the excavation of superdeep foundation pit in new station, the topdown construction of traffic core, and the transformation of large steel structure on the roof of existing station. Therefore, technical measures such as traffic dredging, electronic detonator blasting, grouting reinforcement, field monitoring, topdown construction method, section hoisting simulated by building information modeling technology, and finite element simulation and checking calculation are adopted to ensure the smooth construction of the underground engineering of Dayun hub and the transformation of operational elevated station. The results show that the maximum settlement of pier is only 4.33 mm after grouting reinforcement of elevated station of Line 3; the topdown construction method is adopted to control the structural deformation of the built station, resulting in maximum surface settlement around the traffic core area of 28.19 mm and the maximum horizontal deformation of 22.19 mm.

Key words: metro, stationcity integration, metro transfer hub, deep foundation pit, topdown construction method, protection scheme