Workers in China have made history by completing the world’s largest-diameter underwater shield tunnel, setting a new world record. This achievement is part of the ongoing construction of the Jinan Huanggang Road Yellow River Crossing Tunnel, located in the capital of Shandong Province, Jinan.
The completed section of the tunnel spans two miles and boasts a colossal diameter of 55.8 feet (17 meters). This tunnel section includes 500 pipe rings of underwater shielding, which are key to maintaining the tunnel’s strength and integrity beneath the Yellow River.
Currently, construction continues on the main section of the 3.6-mile tunnel, which will stretch north-south along the Yellow River. This project is being managed by China Railway 14th Bureau Group Co. Ltd. with a focus on enhancing regional transportation and connectivity. Once complete, the tunnel will feature a two-way passage with three lanes in each direction, designed to allow vehicles to travel at speeds of up to 37.2 mph (60 km/h).
One of the most crucial elements in completing this tunnel so quickly is the use of the “Shanhe” shield machine, a tunnel boring machine (TBM) that has played a pivotal role in the excavation process. This machine is known for its incredible efficiency, completing tunneling at a rate of 52.5 to 59 feet (16 to 18 meters) per day, which is a world record for 17-meter-class shield construction.
Manufactured by the German company Herrenknecht, the Shanhe TBM is a mixshield boring machine with an excavation diameter of 57.5 feet (17.5 meters), making it roughly the height of a five-story building. The machine is equipped with a cutter head driver that generates 7,510 horsepower and approximately 25,827,209 lb-ft (35,017 kNm) of torque. These powerful specifications make the Shanhe capable of handling extreme conditions during its tunneling operations.
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The machine is equipped with several advanced features, including a flushing system to prevent clogging and a telescopic camera system that helps monitor the cutting bits and tunnel face as New Atlas explained. These features reduce the need for dangerous and time-consuming manual interventions by maintenance workers.
The construction of such a massive tunnel comes with its challenges. One of the primary issues faced during construction was the treatment of waste slurry, a byproduct of the tunneling process. To address this, the team developed an innovative and environmentally friendly slurry treatment system. This system uses jaw crushers, dual-line pipelines, and a waste slurry concentration and filter press system to handle the excess material effectively and sustainably, the ST Daily report stated.
To overcoming these technical challenges, the team achieved a remarkable feat in terms of time. Construction on the underwater section of the tunnel began on September 1, 2024, and within just 110 days, the underwater shielding portion was completed. This rapid progress set another world record for the completion time of such a large-scale tunneling project.
The Jinan Huanggang Road Yellow River Crossing Tunnel is expected to have a significant impact on the region. The tunnel will not only improve transportation between the north and south sides of the Yellow River but also serve as a key infrastructure link to support the economic integration of Jinan. The tunnel will connect the main urban area of Jinan with a new state-level strategic pilot zone for free trade, innovation, and reform.
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This tunnel is particularly important as it crosses the Yellow River, China’s second-longest river, and will improve traffic flow, making it easier for people and goods to move between different parts of the city and the surrounding regions.
Although the Jinan Huanggang Tunnel will not be the longest underwater tunnel in the world — that title belongs to Japan’s Seikan Tunnel, which stretches 33.46 miles (53.8 kilometers) — it will be one of the most significant in terms of its diameter. The completed section of the tunnel has a diameter of 55.8 feet, making it the largest-diameter underwater shield tunnel ever built.
Once finished, the tunnel will be a six-lane structure, with three lanes in each direction. Its design will support a speed limit of 37.2 mph (60 km/h), and it is expected to ease congestion and improve the overall flow of traffic in the region.
The Jinan Huanggang Road Yellow River Crossing Tunnel is scheduled for completion by late 2025. The ongoing project is not just a technological and engineering achievement but also a symbol of China’s growing capabilities in large-scale infrastructure projects. When finished, it will serve as a vital transportation link, benefiting millions of people and enhancing economic development in the region.
