At 18:18 on January 18, 2022, with the "Yuecheng Liangshan" TBM cutter head breaking out of the rock, the key control project of Lexi Expressway built by China Railway Eighteenth Bureau Group - Daliangshan No. 1 Tunnel The smooth connection of the flat pilot tunnel and the inclined shaft marked the successful completion of the first phase of the overall project of the Daliangshan No. 1 Tunnel 77 days ahead of schedule.

The Daliangshan No. 1 Tunnel of Lexi Expressway is the longest expressway tunnel in Southwest China, and it is also the first expressway tunnel in China that adopts TBM-assisted construction. The tunnel is 15.3 kilometers long and is adjacent to the Dafengding National Nature Reserve, Sichuan Mamize Nature Reserve and other giant panda habitat reserves. In order to protect the natural environment and speed up the construction progress, the China Railway 18th Bureau Group adopted the combined construction method of "TBM flat guide + main hole drilling and blasting method", which filled the blank of domestic expressways using TBM construction technology to assist tunnel construction.

According to the construction task requirements of Daliangshan No. 1 Tunnel, the design guidance period for the first stage of the flat guide and inclined shaft connection is 19 months. Due to the inconvenience of traffic in Liangshan Prefecture and many natural disasters in the rainy season, the TBM equipment arrived later than the scheduled time, and the construction period was delayed. The pressure is tense.

In the face of difficulties and challenges, the project team rose to the challenge, and successively overcame the transportation difficulties and complex geological conditions such as fault fracture zone, gas, water inrush, surrounding rock deformation, etc., and effectively guaranteed and made every effort to promote the continuous, balanced and rapid excavation of TBM.

Since entering the site, the project team has successively set 5 national records for highway tunnel construction. The fastest record; it created the fastest record of China's road excavation of 8,000 meters (manual drilling and blasting of inclined wells + TBM method).

After the flat pilot hole of Daliangshan No. 1 Tunnel is connected with the inclined shaft, the inclined shaft will assist the construction of the main cave of Daliangshan No. 1 Tunnel, and undertake more tasks of construction, transportation and safety of personnel. The tunnel construction will enter the fast lane of acceleration. . Up to now, Daliangshan No. 1 Tunnel has completed a total of 7,856 meters of flat pilot tunnels. It is expected that the contract section of the level pilot tunnel will be completed in January 2023. The left line of the exit has completed a total of 2,116 meters of excavation and support, and the right line has completed a total of 2,116 meters of excavation and support. 3298 meters, it is expected that the main cave will be fully connected in May 2024.Editor/Ma Xue