On January 18, at the construction site of the Jianning West Road river-crossing tunnel in Nanjing, both tunnel tubes were successfully holed through. The shield machine is now being dismantled on site, and the main line of the river-crossing tunnel is scheduled to be completed and opened to traffic in 2025.

Construction site of the Jianning West Road river-crossing tunnel

The Jianning West Road river-crossing tunnel connects the core area of Nanjing Jiangbei New Area with the main urban area south of the Yangtze River. The project starts at the intersection of Xingpu Road and Jiangbei Avenue in Jiangbei New Area, runs south along the east side of Xingpu Road, crosses the Jinpu Railway, and then crosses the Yangtze River in tunnel form. The route is about 6.8 kilometers long. The Jiangbei section is built to urban expressway standards with a design speed of 80 km/h, while the river-crossing section and the Jiangnan section are built to urban arterial road standards with a design speed of 60 km/h.

Interior of the Jianning West Road river-crossing tunnel

The river-crossing section of the project adopts a tunnel scheme, including a shield-driven section 2,380 meters long and open-cut sections to the north and south totaling 1,983 meters. The shield tunnel has an outer diameter of 14.5 meters and accommodates dual tubes with three lanes in each direction; two slurry shield machines were used to bore from north to south. Yu Juncheng, head of the tunnel division, explained that the main-line shield successfully overcame challenges including crossing the most complex strata of the Yangtze River, ultra-high water pressure, crossing the Yangtze River levee, cutting anti-slide piles, passing beneath a Line 5 metro station, and a complex surrounding environment with an ultra-deep receiving shaft, achieving a safe and smooth holing-through of the shield tunnel in the built-up main urban area. This is of great significance for improving China's design, construction, and management levels for large-diameter shield tunnels.

At present, Nanjing is in a critical period of transforming its development model as a megacity and improving urban functions, and is actively working to enhance its carrying capacity as a megacity. The opening of the Jianning West Road river-crossing tunnel is of great significance for promoting integrated economic development across the Yangtze River, improving the urban transportation system, and enhancing the environment of the surrounding areas.