On October 8, a reporter learned from Chongqing Expressway Group that after 28 months of round-the-clock efforts, the right tube of the Hongyan Tunnel on the Chongqing-Hunan Expressway Expansion Project, constructed by China Railway 21st Bureau Group, was successfully holed through.

It is understood that the Hongyan Tunnel is a separated tunnel with left and right tubes; the left tube is 1,666 meters long and the right tube is 1,629 meters long, making it a long tunnel.

The Hongyan Tunnel is located at the junction of the Wuling Mountains and the Dalou Mountains, in a typical karst development area of Southwest China. The tunnel has complex geological conditions, well-developed karst features, and numerous large and small karst caves, and it passes through shallow-buried sections, making construction highly difficult.

A relevant person in charge of Chongqing Expressway Group introduced that during the Mid-Autumn Festival and National Day holiday, the builders of the project department voluntarily gave up their holiday rest and worked on the site to speed up project progress. The successful holing-through of the right tube this time marks a major breakthrough in the construction of long tunnels on the Wudao section of the Chongqing-Hunan Expressway Expansion Project, and lays a solid foundation for the smooth closure of the Guanyinmiao Wujiang Grand Bridge, a controlling project, and the scheduled opening of the Wudao section of the Chongqing-Hunan Expressway Expansion Project.