On October 15, after 18 months of rigorous efforts, the Gongna Tunnel, the only high-gas tunnel on the ongoing Sichuan-Zhongshan Expressway (also known as the Zhan-Guan Expressway), successfully completed its dual-bore construction. This milestone was achieved seven months ahead of schedule, laying a solid foundation for the targeted opening of the Jiang-Tong section by the end of 2026.
The Zhan-Guan Expressway is a critical component of the “Sichuan Provincial Expressway Network Plan (2022-2035),” serving as the third vertical line among 13 planned routes, designed to enhance inter-provincial connections. The expressway stretches a total of 250.825 kilometers, divided into three sections: the Chuan-Shan Border to Wangping segment (60.815 km), Wangping to Tongjiang (33.3 km), and Tongjiang to Guang’an (156.71 km). Importantly, the Wangping to Tongjiang segment already commenced operations on January 18, 2022.
Located in Tongjiang County, Bazhong City, the Gongna Tunnel extends 6,850 meters and is classified as experiencing IV and V grade weak surrounding rock. The construction faced several challenges, including high gas levels, shallow burial, landslide bodies, horizontal rock layers, and the requirement to tunnel under a reservoir, all under high gas conditions that posed substantial risks.
During the construction, the project team implemented rigorous protocols for fire-related activities and adhered to a specialized construction plan for the gas tunnel. They employed controlled blasting techniques to minimize disturbances to the surrounding rock, thereby reducing safety risks. “We have conducted 224 specialized safety training sessions, over 20 technical training sessions, and more than 40 emergency drills to ensure stringent gas management on-site,” said Li Jian, the safety deputy manager for the C1 project of Sichuan Road and Bridge Group, affiliated with Shudao Group.
Furthermore, the construction team integrated advanced technologies into their work, utilizing intelligent machinery to enhance safety and efficiency. “When gas concentration levels change within the tunnel, the ventilation system automatically adjusts to bring gas levels back within safe limits,” explained Pan Yuhang, the deputy general manager of Shudao Expressway Group’s Zhan-Guan Company. This intelligent construction approach has utilized equipment such as truss arching machines and automated reinforcement vehicles, significantly reducing manual labor by 60% and improving overall construction efficiency by 30%. They also introduced smart electrical devices to prevent electrical accidents, safeguarding both personnel and equipment.
Upon its completion, the Zhan-Guan Expressway will connect to several other highways, including the Bawan, Daba, Yingda, Nanda Liang, and Guang’an Ring Expressways. This connectivity is expected to enhance the regional road network, support the development of the Chengdu-Chongqing economic circle, promote the tourism sector along the route, and boost the socio-economic development of the surrounding areas.
