Jinan, China, Dec 24: China has set a new world record with the completion of the world’s largest-diameter underwater shield tunnel. A two-mile section of the massive tunnel, located 98 feet beneath the Yellow River, has been finished, featuring a remarkable diameter of 55.8 feet (17 meters).
The tunnel, which will span a total of 3.6 miles, is being built to improve connectivity in the eastern city of Jinan, Shandong Province. Designed to support a two-way road with three lanes in each direction, the tunnel will enable vehicles to travel at speeds of up to 37.2 mph (60 km/h).
Construction on the tunnel began on September 1, 2024, and in an impressive 110 days, workers successfully completed the underwater shielding, setting a new speed record for such large-scale projects. The tunnel is being constructed by China Railway 14th Bureau Group Co., Ltd, the ST Daily report.
The remarkable speed of the construction was driven by the use of the “Shanhe,” a state-of-the-art mega-boring machine. Manufactured by Herrenknecht, the Shanhe has advanced at a rate of 52.5 to 59 feet per day and 1396.6 feet per month, setting a new world record for 17-meter-class shield construction.
The machine boasts an excavation diameter of 57.5 feet and is powered by 7,510 horsepower with 25,827,209 lb-ft of torque. Its innovative design includes a flushing system to prevent clogging, a telescopic camera system for safer maintenance, and an automatic air cushion that maintains tunnel stability and prevents collapse or flooding.
During the project, the team faced challenges, particularly in dealing with waste slurry treatment. These were overcome through a “pioneering process” that included the installation of jaw crushers, a dual-line pipeline hydraulic quarrying device, and a waste slurry concentration and filter press system, ensuring environmentally friendly tunneling methods.
Once completed, the tunnel will significantly enhance transportation links between the south and north sides of the Yellow River, connecting Jinan’s urban areas with a newly established state-level strategic pilot zone for free trade, innovation, and reform.
Though the tunnel will not be the longest underwater tunnel in the world, it will stand as a major engineering achievement. At 3.6 miles long, it falls short of the Seikan Tunnel in Japan (33.46 miles) and the Channel Tunnel between the UK and France (31.4 miles). The Jinan Huanggang Road Tunnel is expected to be completed by late 2025.
