Wang added that the implementation of nine intelligent systems across sensing, design, construction and management areas has enabled normalized unmanned intelligent boring with algorithmic control.

Engineers have overcome several technical challenges, particularly the complex geology of the Yangtze riverbed, to advance the project.

Li, the chief engineer, said they have addressed obstacles including "the superlarge diameter and long boring distance, navigation through different sediment layers with gas emissions, and simultaneous construction of multiple tunnel components".

The project team has maintained and will continue to maintain strict environmental protection measures, given the tunnel's winding route through residential areas, embankments, anchorage zones and protected aquatic breeding grounds, Li said.

As the project enters its final phase of underwater boring, the focus is on maintaining safety and quality standards, he said, adding that the team is conducting thorough equipment inspections and maintenance while fully utilizing the intelligent construction system to ensure successful completion of the work.

The Shanghai-Nanjing-Hefei high-speed railway represents a crucial section of China's national high-speed railway network. When operational, it will strengthen connectivity between the Shanghai, Nanjing and Hefei metropolitan areas, further advancing the integration of the Yangtze River Delta region.

zhengzheng@chinadaily.com.cn