October 20 (Xinhua) — Reporters learned from China Railway Construction Corporation Limited that on the 20th, after 26 months of tunneling, the left-line shield tunnel of the Jianning West Road river-crossing passage in Nanjing was completed. The tunnel uses a super-large-diameter shield machine with an excavation diameter of 15.07 meters, making it one of the highly difficult projects in tunnel construction across the Yangtze River.

The Jianning West Road river-crossing passage in Nanjing is the river-crossing tunnel closest to the Nanjing Yangtze River Bridge. The left-line tunnel has a total length of 2,674 meters, of which the shield-driven section is 2,349 meters long. It is designed as a dual-bore, six-lane urban arterial road.

According to Mu Zheng, project manager of the China Railway 14th Bureau Group, the maximum water depth of the river-crossing section of the tunnel reaches 55 meters, with high water and soil pressure. The super-large-diameter shield machine must pass through various complex geological conditions, including highly permeable sand layers, soft-hard uneven composite strata, wide fault fracture zones, and fully faced silty clay layers. During tunneling, the builders strengthened monitoring and patrol inspection and precisely controlled the shield machine's posture through a digital management platform, accumulating experience for similar projects.

The Jianning West Road river-crossing passage is an important channel connecting Nanjing's main urban area south of the Yangtze River with the national-level new area north of the river. It is of great significance for enhancing the Yangtze River mainline crossing capacity and improving the regional road network system.