On August 28, at the construction site of the Chengdu-Chongqing Middle Line High-Speed Railway in Lezhi County, Ziyang City, Sichuan Province, the longest tunnel, Wujiawan Tunnel (entrance), was successfully launched into excavation at Section 6 of the Sichuan section of the Chengdu-Chongqing Middle Line undertaken by Sichuan Road & Bridge, marking substantive progress in the project's construction.

Construction site

Wujiawan Tunnel is located in Tongjia Town, Lezhi County. It is designed as a single-tube, double-track tunnel with a total length of 873 meters, a design speed of 350 km/h, and a maximum burial depth of 68 meters. Grade V surrounding rock accounts for 520 meters, or 71% of the total, making it a controlling project of the section.

Wujiawan Tunnel is a micro-gas tunnel and a medium-risk tunnel for floor heave in gently inclined soft rock. To reduce safety risks and schedule pressure, the entire tunnel is constructed using mechanical excavation and bidirectional driving, with multifunctional cantilever roadheaders used for excavation inside the tunnel, further lowering the risks associated with unfavorable geology and shallow-buried tunnel construction.

It is reported that the Chengdu-Chongqing Middle Line High-Speed Railway is an important component of the Yangtze River corridor of China's "Eight Vertical and Eight Horizontal" high-speed rail network. The line starts from Chongqing North Station in the Chongqing hub, runs westward through Chongqing Municipality and Ziyang City and Chengdu City in Sichuan Province, and connects to Chengdu Station in the Chengdu hub, with a main line length of 292 kilometers and a design speed of 350 km/h. Once the project is completed and put into operation, it will further improve the road network structure of the Chengdu-Chongqing region. Travel time from Chengdu to Chongqing North Station is expected to be shortened from the current 1 hour 16 minutes to about 50 minutes, greatly facilitating travel for people along the line and holding great significance for supporting the construction of the Chengdu-Chongqing economic circle and shaping a new pattern of large-scale development in western China.