Recently, the upbound line of the section from Changjiang South Road Station to Tongnan Road Station of Bid 1 of Phase II of Shanghai Rail Transit Line 18 was successfully launched.

The upbound line of the section from Changjiang South Road Station to Tongnan Road Station is 663.429 meters long, with a tunnel crown cover depth of 11.4 to 18.2 meters, a minimum curve radius of 1,000 meters, and a maximum longitudinal slope of 20‰.

The section adopts a new type of socket-type segment, which features high assembly precision and great control difficulty. In addition, the stratum conditions at the shield launching end are relatively complex, and the tunnel bottom is only 2.3 meters away from the ⑦1-1 sandy silt layer containing confined water. To address the shield launching risks, a combined construction process of "cement-based grouting + horizontal freezing + double-sock extended steel ring" was adopted, ensuring the safety and reliability of end reinforcement, avoiding potential risks such as water inrush, running sand, and piping at the gap between the portal ring and the shield outer edge during shield launching, and ensuring the safety of this shield launching.

During the critical period of tackling key difficulties in the project, the Fourth Branch Company and all participating units strictly controlled on-site construction and production safety, refined the work schedule planning, and completed the construction tasks with high quality.