China’s latest advancements in intelligent tunnel boring technology have been successfully demonstrated in the Chongtai Tunnel under the Yangtze River, marking a significant achievement for the Shanghai-Chongqing-Chengdu high-speed railway project. This cutting-edge technology, integrated into the “Pioneer” shield tunnel boring machine, has enhanced the efficiency and quality of the tunnel’s construction process, setting a new benchmark in tunneling operations.
The Chongtai Tunnel, which spans 14.25 kilometers, is a key component of the Shanghai-Chongqing-Chengdu high-speed railway, one of China’s major infrastructure projects. The tunnel will support high-speed rail travel at 350 km/h, making it the fastest underwater tunnel in the world. Out of its total length, 13.20 kilometers were excavated using a shield tunnel boring machine (TBM).
This ambitious tunnel project is managed by Shanghai-Hangzhou High-Speed Railway Passenger Transport Co. Ltd. and constructed by China Railway Tunnel Group (CRTG). The tunnel itself consists of two tracks, with a single entrance at each end. The diameter of the TBM used for excavation is 15.4 meters, while the diameter of the tunnel segments is 14.8 meters. As a result, the Chongtai Tunnel is set to become the largest high-speed railway tunnel globally.
Situated at the deepest part of the Yangtze River, the tunnel faces significant challenges, such as a maximum water pressure of 0.9 MPa. This high-pressure environment necessitated the development of new technologies for both safety and operational effectiveness. The Chongtai Tunnel runs beneath the Yangtze River, connecting Chongming District in Shanghai to Taicang City in Jiangsu, and features some of the most advanced tunneling technology in the world.
The project is notable for its impressive technological innovations. Over 11,325 meters of single-head excavation, the longest in the world, were required to create this tunnel. To ensure the success of this task, nine major intelligent construction technologies were employed, covering every aspect of the project from design and excavation to environmental control and management. One of the most notable achievements was the creation of an intelligent factory for the automated production of tunnel segments. This factory also launched China’s first circular arc segment production line, marking another milestone in the country’s tunneling capabilities.
The most significant technological achievement is the “Pioneer” shield tunnel boring machine itself. Fully integrated with the V2.0 intelligent shield tunneling system, the machine is capable of autonomous operation. This means that while the system is closely monitored, it does not require a human operator, significantly improving both efficiency and safety. As of now, the “Pioneer” machine has successfully completed over 2,600 meters of excavation, traveling through a critical environmental zone known as the Yangtze River knifefish genetic resources protection area, without compromising safety or stability.
Once completed, the Chongtai Tunnel will provide a direct high-speed rail link between Shanghai and Nanjing, significantly reducing travel times and enhancing connectivity between major metropolitan areas. This will mark the first time that high-speed trains can cross the Yangtze River without slowing down, offering a faster, more efficient route for passengers.
The tunnel is also part of a broader effort to improve the national railway network in alignment with China’s Belt and Road Initiative. The Chongtai Tunnel is a critical piece in optimizing the railway network along the Yangtze River, supporting the integrated, high-quality development of the Yangtze River Delta region. Once operational, the tunnel will contribute to the growing importance of the Shanghai-Chongqing-Chengdu high-speed railway, which is a key part of China’s ambitious “eight vertical and eight horizontal” high-speed railway network.
The project has far-reaching implications for the future of high-speed rail in China, offering not only improved transportation within the Yangtze River Delta but also serving as a technological showcase for the potential of intelligent construction systems. By demonstrating the successful application of these advanced tunneling technologies, the Chongtai Tunnel project exemplifies China’s leadership in global infrastructure development, positioning the country at the forefront of intelligent transportation solutions.
