Construction Begins on China's First Large-Diameter Tunnel Under Lake Tai

China's first large-diameter tunnel under Lake Tai enters excavation. Discover how four tunnel boring machines will build the 21.6-kilometer crossing.

Time : Oct 30, 2026

On October 29, 2026, two domestically produced 14-meter-class tunnel boring machines, Pioneer and Xiwang, began excavating the Lake Tai tunnel on the Wuxi-Yixing S2 line from the lakeshore in Wuxi, Jiangsu. The start marks the beginning of excavation on China's first large-diameter shield tunnel beneath the lake.

The lake-crossing section is 21.6 kilometers long. Four 14-meter-class machines are planned to excavate five sections beneath the northwestern waters of Lake Tai.

Construction Begins on China's First Large-Diameter Tunnel Under Lake Tai

What the start of excavation means

The project has moved into the tunneling phase, putting large-diameter shield equipment to work on a long underwater crossing. The use of four machines across five sections also makes progress across the individual sections an important factor in understanding the overall construction schedule.

The simultaneous launch of the first two machines does not by itself indicate how quickly the full crossing will be completed. Subsequent excavation progress and the deployment of the remaining machines will be important developments to watch.