World's Largest-Diameter Undersea High-Speed Railway Tunnel Starts Shield Excavation

The Shantou Bay undersea tunnel in South China's Guangdong Province started shield tunneling on March 29, kicking off the main body construction of China's first undersea high-speed railway tunnel with a designed speed of 350 kilometers per hour.

The 9,781-meter tunnel has an excavation diameter of 14.57 meters, the world's largest diameter of its kind.

It is to be built through complicated strata including an 809-meter full-face granite segment, and four geological fraction zones with intense boulders and several faults. 

The tunnel is a key section of the 162.37-kilometer Shantou-Shanwei high-speed railway which has seven stations. The railway is scheduled to open for service in 2023.

Once operational, it is expected to contribute to the new development paradigm in Guangdong, promote integrated development of east Guangdong and limit travel time between Shantou, Chaozhou and Jieyang to within half an hour, as well as boost development of the region's one-hour economic circle.

A tunnel boring machine is ready to excavate the Shantou Bay undersea tunnel of the Shantou-Shanwei high-speed railway in Guangdong Province [Photo/sasac.gov.cn]

(Executive editor: Wang Ruoting)