On August 26, the right tube of the Punan Tunnel, one of the key and difficult control works of the Jiuzhaigou–Mianyang section of the G8513 Jiuzhaigou–Mianyang Expressway project (hereinafter referred to as the Jiuzhaigou–Mianyang Expressway), was successfully holed through, marking a breakthrough in the construction of the Jiuzhaigou–Mianyang Expressway project and laying a solid foundation for striving to complete and open the entire line to traffic by the end of this year.

The Punan Tunnel is located in Punan Village, Wujiao Town, Jiuzhaigou County, Aba Prefecture, within the Giant Panda National Park. It is a separated long tunnel, with the right tube having a total length of 2,719 meters. The tunnel passes through an ecologically sensitive area and crosses complex geological conditions such as fault fracture zones, shallow cover sections, and water-rich sections. The surrounding rock of the tunnel is Grade V and Grade IV, and the tunnel is characterized by high ecological and environmental protection requirements, high safety risks, strict technical requirements, and great difficulty in design and quality control.

Construction of the Punan Tunnel started on February 1, 2018. During construction, the participating units adhered to green construction and, following the principle of "maximum protection, minimum damage, and maximum restoration," reduced the impact of construction on the environment.

The Jiuzhaigou–Mianyang Expressway project has a total route length of 244.23 kilometers and passes through Jiuzhaigou County in Aba Prefecture and Pingwu County, Beichuan County, Jiangyou City, and Youxian District in Mianyang City. It is an important section of the Pingliang–Mianyang connecting line of the G85 Yinchuan–Kunming Expressway and is also the only typical green highway demonstration project of the Ministry of Transport in Sichuan Province.

As of now, the Jiuzhaigou–Mianyang Expressway project has completed the main construction tasks for 126 bridges and 41 tunnels, with 206 kilometers completed and opened to traffic. After the entire line is completed and opened to traffic, the journey from Chengdu to Jiuzhaigou will be shortened from the original 8 hours to 4 hours, and it will become a major expressway corridor out of Sichuan connecting westward to Gansu, Qinghai, and Xinjiang.