On July 31, it was learned that the four-section invert arch pouring of the airport tunnel exit section has been completed, marking that the airport tunnel exit section has fully entered the main structure construction stage, laying the foundation for the rapid full-line breakthrough of the North Yanjiang High-speed Railway.

The fourth section of the airport tunnel exit section is a major and difficult project on the entire line. The exit section tunnel has a total length of 1300 meters and adopts the open-cut sequential method with section-by-section construction; the fourth section is 370 meters long, and its main structure adopts a fully enclosed self-waterproofing structure. This design can effectively cope with complex hydrogeological environments and improves the durability and safety of the tunnel. Because the construction of the airport tunnel is affected by the foundation pit support system, it is divided into three construction steps: invert arch lining, side wall lining, and arch crown lining.

The invert arch poured this time is a reverse arch structure set at the bottom of the tunnel to improve the stress conditions of the upper support structure of the tunnel, and is one of the important components of the tunnel structure. To ensure the smooth pouring of the first invert arch section, the project team attached great importance to it, planned rigorously, formulated the pouring plan in advance, and organized the on-site deputy production manager and professional engineers to conduct safety technical briefings before concrete pouring. The construction adopts advanced standardized operations to improve the construction safety and quality of the tunnel, providing a strong guarantee for subsequent construction.

In the subsequent construction of the TRD retaining structure and the crown beam concrete support, the project team will continue to optimize the construction organization and steadily advance the construction progress.