Abstract: The statistical analysis shows that the large-diameter and super-large-diameter shield tunnels completed and under construction reach 65 and 59, respectively, as of the end of 2021. Then investigation analysis is conducted on the state-of-the-art of the comprehensive technologies of large-diameter shield tunnels from the perspective of investigation and planning, engineering design, equipment manufacturing, specification, materials, and construction. Moreover, the main issues encountered in large-diameter shield tunnels are highlighted, including nonuniform design standardization, shield key equipment nationalization, difficult refabrication industrialization, and upgrading of vital technologies, and construction technology management. Some specific recommendations are proposed. Finally, it is recommended to follow the principle of tunnel design and shield equipment standardization, and move toward safe, highly-effective, highly-qualified, and highly-intelligent development. The results can provide a positive effect on Chinese comprehensive technologies of large-diameter shield tunnels.

Key words: largediameter shield tunnel, data statistics, comprehensive technologies, essential issues