On October 20 at 10:18 AM, the “Pioneer” shield machine, the world’s largest high-speed rail tunneling machine independently developed in China, successfully completed its 1,000th ring of construction at the Chongtai Yangtze River Tunnel project for the Shanghai-Nanjing-Hefei high-speed rail. This marks a significant milestone in the project’s development.
The Chongtai Yangtze River Tunnel connects Chongming District in Shanghai with Taicang City in Jiangsu Province. The tunnel stretches 14.25 kilometers in total, with a shield construction section of 13.2 kilometers. It is designed for a single bore with dual tracks and boasts several remarkable records: the longest single-bore tunneling distance for high-speed rail (11,325.5 meters), the largest shield diameter (15.4 meters), the highest design speed for crossing the Yangtze River (350 kilometers per hour), and the deepest underwater point in the Yangtze River (89 meters). Once operational, this project will enable high-speed trains to traverse the Yangtze River without reducing speed.
The shielded area between the No. 3 shaft in Chongming District and No. 2 shaft in Taicang utilizes the “Pioneer” shield machine, which measures 128 meters in length and weighs approximately 4,000 tons, with a cutter head diameter of 15.4 meters. It is designed to tunnel southward for a distance of 11,325.5 meters, making it the world’s largest high-speed rail tunneling machine. “The tunneling process will confront engineering challenges such as ultra-long distance excavation, construction organization, slurry circulation, material transport, precise alignment, ventilation management, synchronous lining, and ensuring safety during operation,” stated Liu Jianping, deputy manager of the Chongtai Yangtze River Tunnel project at China Railway Tunnel Group.
To ensure the efficient and smooth operation of the shield machine, the project team has employed advanced design and manufacturing concepts, integrating cutting-edge technologies such as digital twin simulation, intelligent construction with sensory control, visualization, cloud computing, augmented reality, and AI inspections. This has resulted in a comprehensive intelligent construction system comprising eight elements: smart sensing, intelligent excavation, smart assembly, intelligent prefabrication, smart transport, intelligent ventilation, smart detection, and smart control, embedding intelligence throughout the entire tunnel construction process.
Currently, the “Pioneer” shield machine has crossed the northern embankment of the Yangtze River and is tunneling 1,108 meters into the river using a “staffed oversight, automated operation” approach. The geological conditions include alternating layers of hard cemented materials and various permeable strata, accompanied by the presence of harmful gases. Every two meters of tunneling corresponds to the assembly of a ring segment, resulting in a seamlessly integrated and masterfully constructed tunnel.
The Shanghai-Nanjing-Hefei high-speed rail line is a crucial component of the eastern segment of the Shanghai-Chongqing high-speed rail and an essential part of the national “Eight Verticals and Eight Horizontals” high-speed rail network. It will serve as the main transport route for passenger flows along the Yangtze River corridor and parts of the coastal and Beijing-Shanghai routes directly to Shanghai. The completion of this project will establish a rapid new corridor between the Shanghai metropolitan area, the Nanjing metropolitan area, and the Hefei metropolitan area, playing a significant role in developing the “Railway Triangle,” optimizing the railway network layout in the Yangtze River region, supporting the coordinated development of the Yangtze River Economic Belt, and facilitating high-quality integration within the Yangtze River Delta region.