Impressive Progress: Underwater High-Speed Rail Tunnel Under Construction

China has recorded significant progress in high-speed rail infrastructure development after the largest tunnel boring machine, specifically developed for the project, successfully breached the bed of the Yangtze River.

The machine is being utilised in the construction of the Chongtai Tunnel, a project designed to connect Chongming Island in Shanghai with Taicang City in Jiangsu Province through a high-speed rail network.

This drilling success marks a major achievement for China. In addition to supporting the expansion of the transport network, the project reflects advancements in high-tech manufacturing capabilities as well as domestic research and technological capacity.

The project will introduce high-speed rail services to Chongming Island, which is the third-largest island in China.

The boring machine, named Linghang, successfully completed an underwater drilling operation spanning 11.3 kilometres. This represents the longest distance ever traversed by a machine with a 15-metre diameter in a single drilling operation.

The work requires an extremely high level of precision to accommodate trains travelling at 350 km/h, ensuring that once operational, it will serve as an underwater tunnel for one of the fastest high-speed trains in the world.

According to the China Railway Tunnel Group, travelling across the Yangtze River via the tunnel is expected to take only two minutes. The tunnel is situated at a depth of 89 metres below the river surface and is engineered to withstand immense water pressure and the risk of land subsidence.

Wang Yi, Deputy Project Manager of the China Railway Tunnel Group, stated that even minor deviations in the drilling path could affect the safety and comfort of the train journey. Consequently, the precision of the boring machine is being meticulously calculated.

“With a design speed of 350 km/h, we have tightened the precision level of the boring machine to a millimetre scale,” explained Wang Yi.