The world's longest undersea road tunnel achieved a major milestone as the main shielding of the second undersea tunnel of Jiaozhou Bay in Qingdao, east China's Shandong Province, was completed on Tuesday. The section measured 3,258 metres in length, dug using an ultra-large diameter slurry balance shield machine with a diameter of 15.63 metres.
Construction Challenges and Innovations
The construction team overcame significant risks, including high water pressure and crossing fault zones. Innovative methods were employed to ensure success. Gan Congyu, a manager of the tunnel construction project, stated: "Our tunnel boring machine innovatively applies a new method of slag removal, and is equipped with an automated monitoring system for slag and mud, as well as a dynamic tunneling analysis system, to achieve real-time dynamic optimization of tunneling parameters." He added: "This effectively solves problems such as slag stagnation and cutter wear, and ensures that the formed tunnel is leak-proof."
Tunnel Specifications and Impact
The tunnel stretches 17.48 kilometres in total, with a 9.95-kilometre section beneath the sea. It has a designed speed of 80 km/h and will facilitate regional travel. The entire tunnel project is on target for full completion in 2028, with 70 per cent of the work already done. Once finished, transportation links between Qingdao urban area and Huangdao District will be optimised.
