Abstract: The underwater docking construction of shield tunnel and mined tunnel of Xiamen metro line No. 3 is characterized by high water pressure, high risk, and complex geological conditions. In this paper, work breakdown structureresource breakdown structure (WBSRBS) method is used to identify the main risk sources, a risk assessment system is established by the analytic hierarchy process (AHP) method, and a judgment matrix is constructed to conduct risk assessment. Risk assessment results show that the main risk source is weathered groove. Based on the key risk factors, such as shield jamming and stop, crown collapse, and mud burst of weathered groove, countermeasures, including pregrouting, reinforcement strengthening, and shotcreting, are implemented. The successful docking of shield tunnel and mined tunnel indicates the feasibility of the risk assessment accuracy and countermeasures adopted.

Key words:  , underwater/subsea tunnel, tunnel docking, shield penetration, risk assessment, management and control measures