On January 18, the super-large-diameter shield machine "Jincheng No. 1," constructed by China Railway 14th Bureau Group for the Jinggu Haihe Tunnel of the Tianjin-Weifang High-Speed Railway, was successfully launched, marking the official start of tunneling for the high-speed rail shield tunnel with the largest excavation diameter and the longest tunneling distance in the Beijing-Tianjin-Hebei region.

Xie Yuan, Vice Mayor of Tianjin, attended the launch event and announced the start of shield tunneling.

Wu Yankun, Party Secretary and Chairman of China Railway 14th Bureau Group, attended the launch event and stated that the China Railway 14th Bureau team will leverage its experience in large-diameter shield construction and core technical advantages, vigorously advance refined management, strictly control safety and quality, and continuously promote technological innovation to ensure zero defects in project quality, zero safety accidents, and zero delays in schedule. With a high sense of responsibility and mission, they will build the Jinggu Haihe Tunnel of the Tianjin-Weifang High-Speed Railway into a premium and demonstration project.

Wang Zhinan, Party Secretary and Director of the Tianjin Municipal Transportation Commission; Zhang Yongming, Chief Engineer; Chen Bo, Deputy District Mayor of Binhai New Area; Yuan Chungang, Deputy General Manager of Xiong'an High-Speed Railway Company; leaders from China Railway Beijing Group, Jinqin Railway Passenger Dedicated Line Company, China Railway Design Group, China Railway Wuhan Bridge Engineering Consulting and Supervision Company, China Railway Construction Heavy Industry, and other units; as well as relevant personnel from local units, party building co-construction units, and participating construction units attended the launch event. Jiang Wei, a leader of China Railway 14th Bureau Group, presided over the launch event.

The Tianjin-Weifang High-Speed Railway starts from Binhai Station of the Tianjin hub and ends at Weifang North Station of the Jinan-Qingdao High-Speed Railway, with a main line length of 348.9 kilometers, a total of 10 stations, and a design speed of 350 kilometers per hour. The Jinggu Haihe Tunnel, with a total length of about 6.7 kilometers, is the ** tunnel on the entire Tianjin-Weifang High-Speed Railway line. It is constructed using the domestically produced super-large-diameter slurry balance shield machine "Jincheng No. 1," with a maximum excavation diameter of 13.8 meters.

During tunneling, the shield machine will pass beneath a series of major risk sources, including water-rich and soft strata with strong liquefaction potential and other unfavorable geological conditions, as well as the Central Avenue Overpass, the Southwest Ring Railway, and the Haihe River, making construction highly difficult. In addition, the tunnel will immediately pass beneath the nearly millennium-old Changlu Haijing Salt Field at its launch point. The salt pond area has high salinity in the strata, with corrosive ion content approximately 160 times that of a normal stratum environment, placing extremely high demands on the corrosion resistance and stability of shield equipment and reinforced concrete.

To ensure the smooth progress of shield construction, the shield machine is equipped with a synchronous dual-liquid grouting system, a main drive telescopic system, and a synchronous thrusting and segment assembly system, increasing construction efficiency by up to 40% compared with traditional shield construction. At the same time, China Railway 14th Bureau optimized the reinforced concrete mix ratio, carried out anti-corrosion modifications on the shield machine equipment, applied anti-corrosion materials to the shield tunnel segments, and used a full-envelope waterproofing process, enabling safe passage through highly corrosive strata and ensuring the safety, reliability, and long service life of the tunnel.

In addition, the Tianjin-Weifang High-Speed Railway is also a major transportation artery integrating culture and economy. Tianjin's Yangliuqing New Year pictures and Weifang's Yangjiabu New Year pictures are among China's "Four Great New Year Pictures"; Tianjin has "Wei Kites," and Weifang has the "International Kite Festival." During construction, the project fully incorporates traditional Chinese culture and local distinctive culture. The "Jincheng No. 1" shield machine features a "Ruyi Jingu Bang" paint scheme, which is homophonic with "Jingu," symbolizing that all things go as one wishes and peace and smoothness prevail. It is another innovative combination of traditional Chinese culture and a great national heavy machine.

Image of the "Jingu Bang" shield machine's cutterhead being lowered into the shaft

As an important component of China's "Eight Vertical and Eight Horizontal" Beijing-Shanghai auxiliary corridor and coastal corridor, the Tianjin-Weifang High-Speed Railway, once opened to traffic, will add another fast high-speed rail corridor in eastern China, share the pressure of medium- and long-distance passenger flow between Beijing and Shanghai, and effectively alleviate the transportation pressure on the Beijing-Shanghai High-Speed Railway.