Breaking Ground Underwater: Jintang Tunnel Advances High-Speed Rail

Construction of China’s Jintang Undersea Tunnel has taken a significant step forward with the commencement of offshore excavation. Located in Eastern China, this ambitious project is poised to be the world’s longest undersea high-speed railway tunnel. Spanning 16.2 kilometers, the tunnel will connect Ningbo City’s Beilun District to Zhoushan City as part of the 77km Ningbo-Zhoushan Railway, scheduled for completion by 2028.

The Jintang Undersea Tunnel’s design addresses numerous geological challenges, with the tunnel boring machines (TBMs) engineered to manage 28 distinct geological strata transitions. The Yongzhou TBM, stationed in Ningbo, stands at an impressive 135 meters long and weighs 4,350 tonnes, equipped with 308 specially designed cutters to tackle complex marine environments. The project also navigates obstacles such as oil pipelines, seawalls, docks, and major shipping lanes, adding further engineering complexity.

Once operational, the tunnel will drastically reduce travel time between Zhoushan and Ningbo from 1.5 hours to just 30 minutes, enhancing regional connectivity. This improvement is crucial for Zhoushan Port, one of the busiest global freight hubs, facilitating seamless transit under the vital Jintang Channel. Positioned as the world’s third-longest undersea railway tunnel, following Japan's Seikan Tunnel and the Channel Tunnel between the UK and France, the Jintang Tunnel reflects China’s commitment to leading-edge infrastructure development.