Advancements made in construction of the world's longest undersea high-speed tunnel

The construction of the Jintang Tunnel, the world's longest undersea high-speed railway tunnel, has made further headway this month after the Dinghai shield entered the marine section via ground bore.

A 16.18-kilometer undersea tunnel connects Beilun District of Ningbo to Jintang Town of Zhoushan, a major project of the Yongzhou Railway. The section constructed by large shields stretches over 11.21 kilometers.

After its completion, the travel time between Hangzhou and Zhoushan Archipelago will be reduced from 3.5 hours to just 77 minutes.

The Dinghai and Yongzhou shields began simultaneously in May from Zhoushan and Ningbo respectively.

The two shields will be linked under the sea after crossing high water pressure and complicated strata. The Dinghai shield is progressing at the speed of 16 meters per day and soon will break through 1,000 meters. The Yongzhou shield has bored 902 meters and is expected to enter the marine section in May 2025. There is currently no occurrence of subsidence.

The Yongzhou (Ningbo-Zhoushan) Railway is composed of tunnels and bridges. China's railway agency picked an undersea tunnel over a cross-sea bridge to reduce the impact on Ningbo-Zhoushan Port, China's largest port located opposite Jintang Town.

The layout for the Yongzhou Railway begins in Ningbo East Railway Station, passes through Yinzhou and Beilun districts in Ningbo, Jintang, Cezi, and Fuchi islands in Zhoushan, and ends in Dinghai County.

The railway spans 76.4 kilometers and features seven stops, including four new stations (Beilun West, Jintang, Ma'ao and Zhoushan). Three existing stations (Ningbo East, Qiu'ai, and Yunlong) will be renovated with a design speed of 250 km/h.

Yongzhou Railway serves visitors and inter-city commuters in the Yangtze Delta. It proposes to run medium to long-distance trains from Zhoushan to Shanghai, Nanjing, Tianjin, Beijing, Wuhan, Xi'an, Kunming, Guangzhou and Shenzhen.