On September 17, a reporter learned from the Yiyuan County Transport Bureau that the Shiquan Tunnel on the Linlin Expressway, constructed by CCCC First Highway Engineering Co., Ltd., has recently achieved double-tube breakthrough. According to staff of the Yiyuan County Linlin Expressway Construction Command, the Linlin Expressway has a total of 15 tunnels along its entire route, 7 of which are within Yiyuan County. The breakthrough of the Shiquan Tunnel marks the completion of breakthrough for all tunnels within Yiyuan County and has also laid a solid foundation for subsequent construction.

The Shiquan Tunnel is a separated long tunnel, with a left tube 1,221 meters long and a right tube 1,285 meters long. The entrance is designed with a cut-and-cover portal, and the exit is designed with an end-wall portal. The Shiquan Tunnel has a complex geological environment, a narrow construction site, and high construction difficulty. To ensure safe and controllable-quality tunnel construction, the Project Department of Section 7 of the Linlin Expressway strictly followed standardized tunnel construction requirements and, after 532 days of arduous efforts, ultimately achieved the tunnel breakthrough on schedule.

Yiyuan County features undulating mountains and crisscrossing ravines, making highway construction highly difficult; almost every highway project requires cutting through mountains and carving through ridges, filling gullies, and building bridges. The Yiyuan section of the Linlin Expressway passes through nature reserves and karst development areas, and faces problems such as a large number of tunnels, large scale, and high construction difficulty. Based on different geological conditions and construction environments, the project builders boldly innovated and tackled difficulties, carried out scientific design and optimized construction for the tunnels, and actively adopted new technologies and new processes such as complex-environment risk handling and intelligent control, as well as extended-process construction methods, ensuring safe and smooth tunnel construction.