Core Points - The Shanghai Metro Line 22 (Chongming Line) has achieved a significant milestone with the completion of the tunnel for the entire line, marking the longest subway tunnel crossing the Yangtze River in China [1][3] - The completed upward tunnel spans approximately 2,724 meters and faced geological and environmental challenges during construction [1] - The project team implemented advanced techniques to ensure safety and stability during the construction process, including a composite reinforcement method to manage complex water-bearing strata [3] Summary by Sections - **Construction Progress** - The entire tunnel for the Chongming Line has been successfully completed, facilitating subsequent construction phases such as track laying, electromechanical installation, and station decoration [3] - All eight stations of the Chongming Line have completed their main structural caps, and 28 tunnels have been fully connected [3] - **Technical Challenges and Solutions** - The construction faced significant challenges due to high groundwater levels and thick sandy layers, necessitating strict control over ground settlement during tunneling [1] - The project team utilized a combination of "stirring piles + jet grouting + horizontal freezing" techniques to create a reliable frozen curtain, effectively isolating groundwater and ensuring the safe reception of the shield machine [3] - **Impact on Transportation Network** - The completion of the Chongming Line will enhance the integrated transportation network in the Yangtze River Delta, providing more convenient travel options for residents [3]