On October 20, the world’s largest diameter tunnel boring machine (TBM) for high-speed rail, the “Linghang,”working on the Shanghai-Nanjing-Hefei high-speed railway’s Chongtai Yangtze River Tunnel, successfully advanced through its 1,000th ring, reaching a total excavation distance of 2,000 meters.
The Chongtai Yangtze River Tunnel, constructed by China Railway Tunnel Group, connects Chongming District in Shanghai with Taicang City in Jiangsu Province. It has a total length of 14.25 kilometers, with the TBM section spanning 13.2 kilometers. The tunnel features a single-tube, double-track design and holds several world records for high-speed rail tunnels, including the longest single-direction TBM excavation distance (11,325.5 meters), the largest TBM diameter (15.4 meters), the highest under-river design speed (350 kilometers per hour), and the deepest section under the Yangtze River (89 meters).
The “Linghang” TBM, used for the section from Shaft 3 in Chongming to Shaft 2 in Taicang, measures 128 meters in length, weighs approximately 4,000 tons, and has a cutterhead diameter of 15.4 meters. The tunnel entered the TBM excavation phase on April 29 this year and is expected to be fully completed by 2026.
