Construction of the world's largest underwater tunnel has been completed - this is a record
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Construction of the world's largest underwater tunnel has been completed - this is a record

The Chinese city of Jinan, capital of Shandong Province in eastern China with a population of 9,4 million, has made headlines around the world. For good reason: work crews there have completed the monumental task of building the largest underwater tunnel in the world. And this is just part of a grand project to create a vital route through one of China’s largest rivers, the Yellow River.


It is reported that in laying the new tunnel, specialists from the country's largest construction company, China Railway Group, are using the largest tunnel boring machine in existence today. It is still continuing to excavate the main section of the tunnel, which will eventually be 5755 m long. Meanwhile, the underwater section, 3290 m long, has already been completed.

Construction of the world's largest underwater tunnel has been completed - this is a recordShanhe TBM with a shield diameter of 17,6 m during testing. Photo: herrenknecht.com

It has a colossal diameter of approximately 17 m and consists of five hundred underwater protection tube rings, making it the largest structure of its kind in history.

By comparison, the railway tunnels linking the United Kingdom and France are 50,5km long and only about 7,6m in diameter.

The new underground section of the Jinan-Huanggang road will have two levels of traffic – six lanes in each direction. The speed limit is 60 km/h.

The rear of the world's largest Herrenknecht drilling machine. Photo: herrenknecht.com

In addition to the fact that the new infrastructure facility has set a world record due to its size, this large-scale project is also being built at a record pace. Workers began laying the tunnel on September 1, 2024, and, as we know, the underwater part of the shielding has already been completed. And this was done in just 110 days.

The daily speed of the combined shield machine Herrenknecht Shanhe, designed for tunneling with a working diameter equal to a five-story building, was within 16-18 meters, which is also a record for shields of this class.

The Shanhe milling head drive power reaches 7510 hp, and the torque is about 35 kN*m. It is capable of withstanding a maximum pressure of 017 bar. The chamber installed at the working end of the "giant" is also resistant to pressure within 7,5 bar. It received a specialized automatic air cushion, which allows for uniform distribution of the load, maintaining stability and preventing collapses or flooding.

The cutting disc is equipped with an effective flushing system to protect against clogging. It also has a telescopic camera system to monitor the cutting cutters and the tunnel face. This reduces the need for workers to intervene in the equipment for maintenance, which is time-consuming and dangerous.

The Herrenknecht tunnel boring machine, 17,6 m in diameter, costs approximately $80 million. Photo: herrenknecht.com

As for the cost of the Herrenknecht Shanhe, this unique machine is unlikely to cost less than $80 million. The assumption is based on the fact that a buyer from the USA paid $16,46 for a Herrenknecht tunnel boring machine with a shield diameter of 76 meters.

The construction of the tunnel across the Yellow River on the Jinan-Huanggang road is planned to be completed by the end of 2025.
How do you assess the scale and speed of construction in China?
  • Lilu
  • herrenknecht.com, stdaily.com
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