Laoyingpan No.1 Tunnel on the Xichang-Zhaotong Expressway, the world’s longest spiral tunnel invested by CREC and China Railway City Development & Investment Group, surveyed and designed by China Railway Eryuan Engineering Group and constructed by China Railway No.2 Group, was completed.
The left line of the Laoyingpan No.1 Tunnel is 5084 meters long, and the right line under construction is 5014 meters long. It is the longest tunnel in the Xizhao Expressway tunnel group, spiraling around Laoyingpan Mountain. It is 627 meters longer than the world’s longest spiral tunnel, Hankou Tunnel of Xinjin Expressway (4457 meters). The tunnel group has three tunnels, all of which are located in the deep mountains of Jinyang County, Liangshan Prefecture, Sichuan Province.
It is understood that the spiral tunnel is designed with a small radius circular curve, which solves the problem of mountain line climbing by spiral line development. The advantage of using a spiral tunnel is that it can solve the problem of height difference within the horizontal distance of the entrance and exit of the Laoyingpan Tunnel through a long-distance longitudinal slope and skillfully exchange length for height.
After Xizhao Expressway is completed and opened to traffic, it will be connected with the G85 Chongqing-Kunming Expressway and Xixiang Expressway, forming a smooth and convenient sea passage, and Sichuan tourism passage and further strengthening the connection between Chengdu Economic Zone, South Sichuan Economic Zone and Panxi Economic Zone, which will play a positive role in improving the traffic capacity of Sichuan Expressway Network and promoting the economic and social development of the whole province.
