China’s largest shield tunnelling machine built for high-speed rail has successfully carved a path beneath the Yangtze River, a milestone expected to help strengthen the country’s hi-tech manufacturing supply chains and advanced research capacity.
The Chongtai Yangtze River Tunnel, scheduled for completion by the end of this year, will connect Shanghai’s Chongming Island with Taicang in neighbouring Jiangsu province. For the first time, the project will bring high-speed rail services to the island, the country’s third-largest.
The machine, dubbed “Linghang”, completed an 11.3km (7-mile) underwater stretch – the longest distance ever bored by a 15-metre-wide model in a single run, state news agency Xinhua reported on Thursday. The work demands extreme technical precision to accommodate trains scheduled to run at 350km/h (217.5mph), making it the fastest underwater high-speed tunnel worldwide once operational.
Crossing the Yangtze River inside the tunnel is projected to take two minutes, according to China Railway Tunnel Group, a state-owned firm working on the project. Operating 89 metres (292 feet) beneath the waterway, the structure is engineered to withstand heavy water pressure and ground settlement risks.
“Even minor alignment deviations during excavation could compromise rail travel safety and comfort,” Wang Yi, deputy project manager at China Railway Tunnel Group, told Shanghai-based news outlet The Paper in April.
“With a design speed of 350 km/h (217.5mph), we have tightened precision requirements for the tunnelling machine to the millimetre scale.”
Such massive boring machines rely on a rotating metal-cutting wheel, hydraulic thrust jacks and a protective outer steel casing to excavate and reinforce underground paths.
The Chongtai project is estimated to require total investment exceeding 7.1 billion yuan (US$1.05 billion), according to an April report by Shanghai-based financial news outlet Yicai.
It forms a crucial section of the Shanghai-Chongqing-Chengdu High-Speed Railway, a major artery linking three metropolitan clusters spanning coastal and inland regions. The full high-speed rail line is projected to require total investment of more than 530 billion yuan (US$78.42 billion), The Paper reported.
Once fully operational, the line will form a roughly 2,000-kilometre (1,243 miles) economic corridor connecting more than a quarter of the country’s advanced manufacturing clusters and 40 per cent of its strategic state laboratories, according to figures in a March report by state-owned broadcaster China Global Television Network.
“The ‘Linghang’ shield tunnelling machine proves China has mastered core technologies for high-speed underwater rail tunnels,” said Wang of the China Railway Tunnel Group.
“The Chongtai Yangtze River Tunnel delivers a replicable and scalable Chinese solution for future infrastructure projects.” -- SOUTH CHINA MORNING POST
