At 11:00 a.m. on October 13, 2022, the high-profile "Guizhou First Tunnel" - Chongzun Expansion Project Tongzi Tunnel was successfully connected to the right side, so far Tongzi Tunnel has entered the countdown of full connection. With more than 300 constructors, the right side of Tongzi Tunnel, which was constructed by Guizhou Highway Group, was successfully connected after 4 and a half years of difficult construction.

Tongzi Tunnel with a total length of 10.497km is the longest tunnel of Chongqing Zunyi Section (Guizhou) Expansion Project of Lanzhou Haikou National Expressway, the longest tunnel of expressway in Guizhou Province and the tunnel with the longest ventilation mileage of single end tunneling. The first tunnel with a single head tunneling of more than 4.7 km is also among the three lane tunnels of the same type under construction in China.

Tongzi Tunnel can be called the throat project of the whole line of Chongzun Expansion Project, and it is the tunnel with the most complicated geology and the most difficult construction.Editor/Ma Xue