China completes technical work for longest undersea rail tunnel

Planning for China’s longest undersea rail tunnel, between the city of Ningbo and the island of Zhoushan, about 60km south of Shanghai, has been completed, the Ningbo Evening News reported on Saturday.

Technical work on the 16.2km tunnel has been under way for the past two years. These proposals were last week approved by a panel of experts headed by Qian Qihu, a member of the Chinese Academy of Engineering who specialises in tunnelling.

The tunnel will carry road traffic and a section of the 77km Ningbo-Zhoushan high-speed rail line, which will run through the tunnel and over several bridges from Ningbo to Zhoushan via Jintang Island.

The lengthy planning period was necessitated by the decision to build the 14m-diameter tunnel with a maximum depth of 78m using an 11km-long undersea shield.

When completed, the link will allow trains traveling at 250 km/h to go from Ningbo to Zhoushan in just 30 minutes, compared with 1.5 hours by car over the Ningbo sea bridge (pictured). Trains using the tunnel will be able to travel from Hangzhou, the capital of Zhejiang province, to Zhoushan in 80 minutes.

Officials said construction of the line is likely to start this year, with the project to take six to seven years to complete. Drilling work to lay the foundation for the tunnel was completed in May.

Zhoushan is made up of an archipelago of islands in the south of Hangzhou Bay. It has a population of about 1.1 million.

Image: The 26.6km Ningbo to Zhoushan sea bridge (Liujinguang/CC BY-SA 2.0)

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