Start shield tunneling for the longest underwater road tunnel

On June 30th, workers monitored and maintained the operation of the shield tunneling machine in the service tunnel.The reporter learned from China Railway Construction Corporation Co

On June 30th, workers monitored and maintained the operation of the shield tunneling machine in the service tunnel.

The reporter learned from China Railway Construction Corporation Co., Ltd. that on June 30, the "National Signal" shield machine successfully started at Qingdao Port Terminal 8, marking the beginning of the excavation of the shield section of the second Jiaozhou Bay tunnel project, the longest undersea road tunnel in China designed by China Railway Construction Corporation Fourth Design Institute and constructed by China Railway 14th Bureau, and opening the "journey across the sea" across Jiaozhou Bay.

According to Xiao Mingqing, the project design director of the Fourth Railway Research Institute, the main line of the second tunnel project in Jiaozhou Bay is 17.48 kilometers long, of which the sea section adopts the layout of "two main line tunnels+intermediate service tunnels". According to the different geological conditions and construction environment, the design adopts the combined construction method of drilling and blasting and shield structure to cross Jiaozhou Bay.

Wang Junping, the technical director of the project of China Railway 14th Bureau, told reporters that the second Jiaozhou Bay subsea tunnel has complex geology and passes through many fracture zones and soft upper and hard lower strata. In shield tunneling, the builder will use three shield tunneling machines for construction, including two main tunnel shield machines with a diameter of 15.63 meters and one intermediate service tunnel shield machine with a diameter of 8.18 meters. The main machine of the "National Signal" shield tunneling machine that started this time has a total length of 180 meters and a total weight of 1686 tons, used for intermediate service tunnel construction. After completion, this tunnel will serve as a ventilation, maintenance and emergency rescue channel to meet the needs of large flow and extra long subsea tunnel operation.

In response to the complex geological conditions, high water pressure, and long-distance hard rock excavation problems in the shield tunneling section, the "National Signal" shield tunneling machine is equipped with a series of intelligent systems such as a telescopic main drive and a telescopic excavation warehouse monitoring system. At the same time, multiple cutting-edge technologies such as synchronous double fluid grouting and synchronous assembly are applied to ensure safe and stable excavation.

It is reported that the second tunnel of Jiaozhou Bay is planned to be completed and opened to traffic in December 2027. At that time, Qingdao will enter the "double tunnel era", which is of great significance for the optimization of Qingdao's urban spatial structure, the integrated development around Jiaozhou Bay, and the overall competitiveness of Jiaodong Peninsula urban agglomeration. Wen Bingtu/Xinhua News Agency

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