Abstract: A comprehensive physical simulation platform is currently lacking for the five critical processes—small-angle shield shell drilling, high water pressure grouting, leakage emergency handling, freezing wall thermal operation, and steel shell concrete filling—involved in shield docking within high water pressure and highly permeable strata. To overcome this limitation, a case study is conducted on the Jiangyin-Jingjiang Yangtze River Tunnel, and a multistage progressive full-scale model test platform is designed and developed. Under the design concept of functional zoning, controllable parameters, and multifield coupling, this platform adopts a full-scale steel structure box as its primary framework. It integrates pressure stabilization and freezing systems, enabling realistic simulations of complex geological conditions, including 1.0-MPa high water pressure and strong permeability. The platform integrates the interfaces of drilling, grouting, leakage emergency handling, freezing wall thermal operation, and steel shell concrete filling test modules, facilitating multistage progressive experimental research on the aforementioned key shield docking processes. A thermal operation test under freezing wall conditions was conducted using this platform, which verified the reliability of its monitoring system and simulation environment. The results indicate that among the three designed thermal operation conditions, the 100-mm thick cutterhead steel plate cutting condition exerts a relatively significant temperature influence. Under the tested freezing conditions, the maximum melting length at the shield shell and frozen soil interface is approximately 46.16 cm, representing 2.46% of the designed frozen wall length. The maximum melting thickness of the frozen soil is approximately 15.83 cm, accounting for 4.06% of the designed frozen wall thickness.

Key words: high water pressure and highly permeable strata, underground docking of shield tunnels, multistage progressive approach, full-scale model test platform, platform design