The shield machine dubbed "Hehe" finishes the east line of Taizhou's Jiefang Lu river-crossing tunnel. [Photo/Tide News]

The east line of Taizhou's Jiefang Lu river-crossing tunnel was completed on June 23 after a 15.01-meter-diameter shield machine broke through underground layers beneath the Jiaojiang River, marking a key milestone in the city's first cross-river tunnel project.

The shield machine, named "Hehe", completed excavation of the 1,806-meter east tunnel section, part of a major infrastructure project designed to improve north–south urban connectivity across Taizhou in East China's Zhejiang province.

Once fully completed, the 4,220-meter tunnel is expected to reduce travel time between the two sides of the river from about 25 minutes by road to around 5 minutes, significantly easing congestion during peak commuting hours.

The project faced complex geological conditions, including soft soil layers prone to collapse and high groundwater pressure. The 4,500-metric-ton shield machine is equipped with an intelligent control system that can adjust tunneling parameters in real time based on underground conditions, improving stability and precision during excavation.

Wang Yuntao, manager of the project, said the east line breakthrough marks the completion of one phase rather than the end of construction. The shield machine is now undergoing inspection and system adjustments before beginning work on the west line, which will extend a further 1,822 meters.