In the 21st century, the underwater tunnels have advanced rapidly in China. A large number of projects, completed or ongoing, have greatly promoted the advancement of underwater shield tunnel technologies in China and in the world. The development history of the underwater tunnels in China is summarized, and the technical challenges and breakthroughs encountered and achieved during the construction of many tunnels are presented, as represented by Nanjing Yangtze River Tunnel and Shiziyang Tunnel of GuangzhouShenzhenHong Kong Highspeed Railway. The characteristics and challenges of some representative underwater tunnels during construction, including RoadRailway Yangtze River Tunnel in Sanyang Road, Shiziyang Tunnel of FoshanDongguan Intercity Railway, Yangtze River Tunnel of SuzhouNantong UHV Power Transmission and Transformation Project; and projects to be constructed, such as Pearl River Estuary Tunnel of ShenzhenMaoming Railway, Shantou Bay Subsea Tunnel of ShantouShanwei Highspeed Railway, and Nanjing Heyan Road Yangtze River Tunnel, are presented as well. The development trend of China′s underwater shield tunnels, including from single soft soil formation to complex soil formation, from large diameter to super large diameter, from medium water pressure to high and ultrahigh water pressure, from ordinary to special and unfavorable geological conditions, from seismic regions with moderate intensity to those with high intensity, and from single construction method to combination of multiple methods, are analyzed. It is pointed out that the technical fields still require further study and innovation, and the areas still require further enhancement and innovation, such as the norms, codes, designs, constructions, equipment, materials and management.

进入21世纪以来，我国水下隧道进入快速发展阶段，取得了辉煌的成就，一大批已建和在建工程极大推进了我国乃至世界水下盾构隧道技术的进步。概述我国水下隧道的发展历史，总结南京长江隧道和广深港高铁狮子洋隧道等代表性已建水下隧道的技术难题和主要技术进步，梳理武汉三阳路长江隧道、佛莞城际铁路狮子洋隧道和苏通特高压输变电工程长江隧道等在建的代表性水下隧道和深茂铁路珠江口隧道、汕头湾海底隧道、南京和燕路长江隧道等拟建代表性水下隧道的特点和难点。进一步分析我国水下盾构隧道的发展趋势： 由单一软土地层向土砂复合地层发展、由大直径向超大直径发展、由中等水压向高水压和超高水压发展、由常规岩土向特殊岩土和不良地质发展、由中等烈度地震区向高烈度地震区发展、由单一工法向多工法组合发展，并提出需要加强研究与创新的技术难题。我国水下隧道仍将处于高速发展期，需从规范、标准、地质勘察、设计、施工与管理、装备和材料等方面不断完善和创新。