On April 18, at the construction site of the Jintang Submarine Tunnel of the Yongzhou Railway undertaken by the 14th Bureau of China Railway, the cutterhead of the shield machine with a diameter of 14.57 meters and a weight of 460 tons was successfully hoisted into the shaft, marking the completion of the assembly of the "Yongzhou" shield machine and the countdown to the launch of the world's longest submarine high-speed rail tunnel shield machine.
With a total length of 135 meters and a weight of 4,350 tons, the shield machine will start from the Ningbo working shaft and excavate 4,940 meters in the direction of Zhoushan, passing through many complex formations such as soft and hard at the bottom and geological structure zones for a long distance, and finally achieve precise docking with the "Dinghai" shield machine on the Zhoushan side on the seabed.
Since February 26, the "Yongzhou" shield machine has been accepted and rolled off the assembly line in Changsha, Hunan Province, and has been transported by road and waterway throughout the whole process, and has arrived in Ningbo in stages for assembly. Among them, the cutterhead of the shield machine is the largest single component of the shield machine, which needs to be split into 5 pieces and transported to the construction site, and then leveled and welded.
Han Fengqi, chief engineer of the Yongzhou Railway Project of China Railway 14th Bureau, introduced that the shield launch shaft at the Ningbo end of the Jintang Submarine Tunnel is 58 meters deep, which is currently the deepest large-diameter shield launch shaft in China.
In order to ensure the smooth launching of the cutterhead of the shield machine, the project team customized the lifting rope and winch, and after 7 simulations, analyzed the surrounding environment of the cutterhead hoisting in detail, reasonably arranged the construction site, and carefully designed the cutterhead hoisting route. With the close cooperation of surface and underground operators, through the precise cooperation of two crawler cranes with a lifting capacity of 800 tons and 400 tons, through a series of operations such as lifting, turning over and rotating, the precise docking of the cutterhead and the main drive is finally realized.
After the completion of the cutterhead positioning and installation, the work of shield machine pipeline connection, system no-load test and joint commissioning of the whole machine will be started one after another, so as to prepare for the subsequent launch of the shield machine.
Edited by Sha Kaidi
Text: Lee Teng-hui and Ma Jingbo
Process Editor|Chen Shang
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