On the 29th, the Changsheng Extra-Long Tunnel, a key control project of the Zhenguan Expressway, achieved full breakthrough across both tubes. With this, after 10 months of construction, the A2 contract section of the Zhenguan Expressway, undertaken by the Highway Tunnel Branch of Sichuan Road & Bridge Group under Shudao Group, took the lead in achieving full breakthrough of the Wangping-Tongjiang section.

According to reports, the Zhenguan Expressway is a highway from Zhenba in Shaanxi to Guang'an in Sichuan, with a total length of about 270 kilometers, linking the Chengdu-Chongqing and Guanzhong-Tianshui economic zones. Because it is located in the Qinling-Daba Mountains and the Sichuan-Shaanxi old revolutionary base area, it is known as the "Red Expressway." The A2 contract section of the Zhenguan Expressway is about 9 kilometers long, with a bridge-to-tunnel ratio of 67%, of which the Changsheng Extra-Long Tunnel is 3.57 kilometers long.

Since construction began in September 2020, the project department has overcome numerous difficulties such as terrain restrictions, inconvenient transportation, flood-season risks, material shortages, and tight schedules with heavy tasks. Guided by the requirement to "start work upon commencement and go all out upon starting," it successively achieved the first tunnel portal entry on the entire line, the first subgrade acceptance, the first single-tube breakthrough, and the first full breakthrough. At the same time, in tunnel construction, using a "short, tight, fast, and excellent" model, it set a record of an average of 519 meters completed per month, setting a new speed for similar expressway tunnel construction.

During construction, the A2 contract section of the Zhenguan Expressway vigorously promoted and applied the "four new technologies": in tunnel construction, it adopted shaped-charge smooth blasting technology, wet spraying technology, and the walking telescopic widening belt secondary lining trolley plus distribution system method, among others, shortening the construction period and reducing costs while ensuring construction quality and safety; in bridge construction, the project applied hydraulic climbing formwork, prefabricated pedestal methods, and prestressed prefabricated girder methods, among others, comprehensively improving the smoothness and production efficiency of bridge deck paving.