On September 7, the left tube of the Maowanchong Tunnel on the Zhangjiajie-Guzhang Expressway in Yuanling County, Huaihua City, was successfully and precisely holed through, marking new progress in tunnel construction on the Zhang-Guan Expressway and laying a solid foundation for the completion and opening of the entire line.

　　The Maowanchong Tunnel is a two-way, four-lane tunnel and is a key project and major control works of the Zhangjiajie-Guzhang Expressway project. It is a long tunnel: the left tube runs from chainage ZK58+325 to ZK59+700, with a total length of 1,375 m; the right tube runs from chainage K58+327 to K59+688, with a total length of 1,361 m. The clear distance between the left and right tubes is 14.07–31.61 m; it is a separated tunnel with a small clear-distance layout at the portals, adopting end-wall type portal structures. The tunnel contains 4 pedestrian cross passages and 1 vehicular cross passage, and each tube has one emergency parking bay. The natural slope of the mountain within the tunnel centerline range is 30°–45°, with well-developed vegetation; the portals are located in the sloping zone at the foot of the mountain, and the maximum cover depth is 155 m. The tunnel passes through a fractured geological zone, with the rock mass mainly consisting of moderately weathered metasandstone.

　　During construction, with the full support and on-site guidance of the owner, design, supervision and other units, the project team of Bid Section 2 of the Hunan Expressway Group for the G59 Zhang-Guan section promptly adjusted construction techniques and methods according to the surrounding rock conditions, adopting the bench method and other approaches for construction, and used advanced scientific detection means such as advanced drilling, ground-penetrating radar and TSP to accurately grasp the geological conditions ahead of the tunnel face in real time. At the same time, domestic advanced equipment and technologies such as wet shotcrete manipulators, hydraulic secondary lining trolleys and the ACS access control system were adopted to achieve mechanized and intelligent construction and ensure project safety, quality and progress.