The cutter head of the Haitian Hao tunnel boring machine used in the construction of the world's largest and longest subsea road tunnel – the second Qingdao Jiaozhou Bay undersea tunnel project built by China Railway 14th Bureau Group Corporation Limited – was successfully installed on Nov 13.
The cutter head of Haitian Hao tunnel boring machine used in the construction of the world's largest and longest subsea road tunnel - the second Qingdao Jiaozhou Bay undersea tunnel project - is installed on Nov 13. [Photo/sasac.gov.cn]
The "Haitian Hao" tunnel boring machine is working on the shield section of the southern section of the main line of the second Jiaozhou Bay Tunnel project, with a total excavation length of 3,255 meters. The shield machine has a tunnel excavation diameter of 15.63 meters, a total length of 142 meters, and weighs over 5,000 tons. It is equipped with intelligent systems, including a telescopic main drive and a telescopic excavation chamber monitoring system.
The cutter head is the largest single component of the "Haitian Hao" tunnel boring machine. To ensure the safety and stability of the lifting operation for this oversized component, the project team meticulously planned and studied the hoisting scheme. The successful installation of the cutter head lays a solid foundation for the commencement of the tunneling phase of the world's longest subsea road tunnel.
The tunnel boring machine will start tunneling from the tunnel shaft located in Qingdao Port, heading west towards the coast, where it will connect with the drill and blast section of the tunnel under the seabed, traversing various complex geological conditions. The machine will pass through soft upper and hard lower strata, full-section hard rock, and multiple fault fracture zones. The maximum burial depth is 68.5 meters and the maximum water pressure reaches 9.4 bar, which is equivalent to bearing a pressure of 9.4 kilograms on a fingernail-sized area.
The second Jiaozhou Bay tunnel project is a major provincial-level construction project in East China's Shandong Province. It adopts a layout of twin tunnels with six lanes in two directions plus a middle service tunnel. Once completed and open to traffic, it will help Qingdao break through urban space growth, facilitate the coordinated development of the eastern and western shores of Jiaozhou Bay, and enhance the overall competitiveness of the Jiaodong Peninsula urban agglomeration.
(Executive editor: Xie Yunxiao)
