79 Percent of Zheduo Mountain Tunnel Excavation Completed

Dragon Media Correspondent

Excavation of the Zheduo Mountain Tunnel on China’s National Highway 318 in Sichuan Province is 79 percent complete. Construction began in 2018, and the project is targeted for completion by the end of 2027. Once completed, the tunnel is expected to cut travel time between Kangding and Xinduqiao from two hours to one.

Workers and construction vehicles inside the tunnel are tracked in real time from an intelligent control centre. A video monitoring system also keeps watch over construction around the clock. The system helps maintain construction quality and protect workers, said Wang Qiang, a deputy chief engineer on the project.

The surrounding rock is soft and fragile. It can turn muddy when wet, while water inflow into the tunnel has added to the construction challenges. For an extended period, blasting and tunnel-boring machines could not be used, leaving excavators to advance the work at a pace of about 2.5 metres a day.

The construction team has adopted a non-blasting excavation method using excavators fitted with high-frequency vibration hammers. It has also deployed large machinery, including three-arm rock-drilling rigs, arch installation platforms and high-capacity wet-spraying machines. The new methods have helped reduce the risk of rock collapse and improve construction speed, according to the project team.

The tunnel is now advancing by an average of five metres a day. Since the beginning of this year, workers have excavated 1,031 metres, reaching 74 percent of the annual target.