By rosebell
TBM Jianghai, which is going to excavate the Haitai Yangtze River Tunnel in east China’s Jiangsu Province that is one of the world’s longest underwater road tunnels, has been commissioned in China.
Linking Haimen in the city of Nantong with Taicang in the city of Suzhou, this tunnel is a key project for a major trans-river road link under China’s longest river.
With a maximum excavation diameter of 16.6m, this machine is almost 145m long and weighs 5,000 tonnes and the responsibility of its designe and developing was up to China Railway Construction Heavy Industry Corp in collaboration with China Railway 14th Bureau Group.
Comprising of an 11.18km underwater section, with 9.3km to be excavated by TBM,this tunnel extends approximately 39.07km. It is designed as a six-lane, bi-directional highway with a speed limit of 100km/h.
The geology of tunnel alignment is complex and involves formations beneath the riverbed, including layers of silt and fine sand.
“It will reach a maximum depth of 75m, subjecting it to pressure equivalent to 75 tonnes per square metre.These harsh conditions make the construction process extremely challenging,” said You Shaoqiang, chief engineer of the tunnel project of China Railway 14th Bureau.
In order to overcoming geological conditions and enabling real-time monitoring of cutterhead wear and facilitates tool repair or replacement within the underwater working cabin,TBM Jianghai is equipped with a pressure-balanced cutterhead and an intelligent monitoring system which also features dual slurry injection to improve efficiency.
Additionally, with the aim of mitigating fire risks, the project team has devised a segmented smoke extraction system and have incorporated a dedicated rescue vehicle access tunnel, which is connected to the main tunnel via corridors, for swift rescue operations without disrupting other traffic in the tunnel.
According to Chen Junwei, a manager of the tunnel project:”The tunnel boasts multiple pioneering features in structural design, disaster prevention, equipment, green technology, and intelligent systems, with its construction designed to be close to carbon neutral.”
The scheduled date for completion of this tunnel is 2028.
