Abstract: With the rapid development of underwater tunnel construction, underground shield docking has become a key technology for realizing long-distance tunneling in complex strata. A case study on the Jiangyin-Jingjiang Yangtze River Tunnel Project is conducted to address the technical challenges faced by docking super-large-diameter shields at the riverbed under high water pressure and strongly permeable sandy strata. A full-process technical path for docking is established based on the concept of dividing the shield docking technology zone. To address the core challenges during the implementation of this technical path, the following technical measures are proposed. The composite reinforcement of the shield body with longitudinal and circumferential ribs, together with segment tieback technology in the transition zone, ensures structural safety during shield stoppage and dismantling. Furthermore, a micro-disturbance tunneling control system based on a response evaluation model is established, enabling the dynamic protection of the leading structure by the trailing shield. A high-precision docking control method is developed by integrating precision measurement and intelligent deviation correction technology, which achieves precise docking with a horizontal trend different of 0 mm and a vertical trend different of 2 mm. A composite reinforcement process combining grouting and freezing creates a stable and impermeable working environment. Furthermore, the modular dismantling and graded unloading of the core section enable the safe removal of large-tonnage components within the tunnel. Finally, a convenient two-phase construction and three-layer steel plate approach is used to construct the steel-shell-concrete structure of the closure section, which exhibits sufficient bearing capacity. This series of technologies is successfully applied in the Jiangyin-Jingjiang Yangtze River Tunnel Project. After construction, the maximum horizontal deviation of the tunnel breakthrough is 1.2 mm, the vertical deviation is 3.2 mm, the maximum segment horizontal displacement is 1.5 mm, and the maximum shield thaw settlement is 12.61 mm. The construction process is safe and controllable, providing a complete technical system and a practical example of underground shield tunnel docking under similar conditions.

Key words: shield tunnel, high water pressure and highly permeable stratum, underground docking, micro-disturbance tunneling, steel-shell concrete