Jinan, the capital of Shandong Province in East China, has made global headlines with the completion of the world’s largest-diameter underwater shield tunnel. The monumental achievement was made possible by the China Railway 14th Bureau Group Co., Ltd., which is still in the process of excavating the 3.6-mile (5,755 meters) tunnel, with the 2-mile (3,290 meters) underwater shield section already finished.
The completed section of the tunnel boasts an impressive diameter of 55.8 feet (17 meters) and is composed of 500 pipe rings of underwater shielding. This makes it the largest tunnel of its kind anywhere in the world, surpassing previous records set by other significant global projects like the Channel Tunnel, which connects the UK and France.
The Jinan Huanggang tunnel will feature a double-decker design with six travel lanes in each direction, providing a critical north-south passage across China’s second-longest river, the Yellow River. The tunnel will play a pivotal role in enhancing connectivity between Jinan’s urban center and its rapidly transforming regions.
Not only has the project set a world record for size, but the team also achieved a remarkable milestone in efficiency. The underwater section was completed in just 110 days, with the Herrenknecht “Shanhe” shield machine advancing between 52.5 and 59 feet (16 to 18 meters) per day, setting a new world record for the 17-meter-class shield construction.
This record-breaking feat is facilitated by the immense power and advanced technology of the “Shanhe” Tunnel Boring Machine (TBM), which features a cutterhead driver with 7,510 horsepower and a torque of nearly 26 million lb-ft. With its impressive specifications, the machine is designed to withstand pressures up to 7.5 times normal atmospheric levels and can operate in extreme conditions.
The Jinan Huanggang tunnel is slated for full completion in late 2025, further advancing China’s infrastructure ambitions while setting new global standards for tunneling projects.
