China News Service, Changsha, February 26th (to Yipeng Li Guixiang and Ma Jingbo) On the 26th, the super-large-diameter shield machine "Yongzhou" with a cutterhead painted with "Ruilong" pattern rolled off the assembly line in Changsha, Hunan, and will be used for Construction of the world's longest undersea high-speed rail tunnel - the Jintang Undersea Tunnel of the Ningbo-Zhou Railway.

On February 26, the shield machine "Yongzhou" that will be used in the world's longest undersea high-speed rail tunnel rolled off the assembly line in Changsha.

Photo by Yang Huafeng

  The equipment has a total length of 135 meters, a total weight of 4,350 tons, a cutterhead excavation diameter of 14.57 meters, and is equipped with 308 special tools. Its final assembly has reached world-class level. It was jointly developed by China Railway 14th Bureau Group and China Railway Construction Heavy Industry Group.

  It is understood that the "Yongzhou" shield machine not only has to penetrate 42 risk sources such as 23 oil pipelines, ground buildings, seawalls, docks, and main channels, but also has to face complex strata and sea environments. Rocks and unevenly hard and soft strata account for nearly 70%, with the highest strength reaching 200 MPa.

The interval will face 14 alternating transitions between soft and hard strata, long-distance crossings with great differences, and frequent manual high-pressure tool changing operations on the 70-meter-deep seabed. The construction complexity, difficulty, and risks are unique in the world.

  Hu Hao, director of the Ningbo-Zhou Railway Project of the China Railway 14th Bureau, introduced that in view of the complex construction characteristics of the undersea tunnel, the project team carried out 6 innovative designs for the shield machine, including double-layer shells and simultaneous double-liquid grouting, using heavy-duty pressurized The cutterhead design adds 70 hobs and more than 100 tons of weight than the conventional cutterhead, and reduces the distance between the cutters. It is the first time in the world to develop and apply an intelligent hob wear monitoring system. The cutterhead has stronger wear resistance and rock-breaking ability. , to ensure excavation efficiency.

  "The shield machine uses the guidance system with the highest control accuracy and the most advanced technology as the 'eye' for the equipment's excavation. It is equipped with special equipment such as advanced geological prediction and advanced grouting reinforcement, which can carry out unfavorable geology in front of the shield machine's excavation. Advance detection and advance reinforcement," Hu Hao said.

  It is reported that the Ningbo-Zhou Railway project has a total length of approximately 77 kilometers and a design speed of 250 kilometers per hour. It is to build a "one-hour traffic circle" in Zhejiang Province and form a convenient passenger transportation channel between the mainland and Zhoushan Island.

The Jintang Undersea Tunnel is a full-line control project, starting from Yinzhou District, Ningbo City in the west, to Jintang Town, Zhoushan City in the east, with a total length of 16.18 kilometers, of which the shield section exceeds 11 kilometers.