Abstract:

New Yuelongmen Tunnel of Chengdu-Lanzhou Railway passes through the famous Longmen Mountains in China, which has a controlled construction period along the whole railway line. The construction organization of Yuelongmen Tunnel is affected by many factors including unfavorable geology (e. g. high in-situ stress, high temperature, high gas and H2S, large deformation of soft rock, active fault zone and water-rich karst), and secondary geological hazards (e. g. landslide and debris flow after 2018 Wenchuan Earthquake). In addition, the dead-end distance of tunnel construction ventilation in the construction site of No. 3 inclined shaft reaches 8 km, and the section is adjusted due to the "tunnel group effect" of large deformation of soft rock, increasing the out-shift parallel adits, resulting in a " 2+1+1" tunnel structure (four tracks parallel to each other), high-gas ventilation and a sharp increase in difficulties of logistics transportation. These lead to substantial challenges in dynamic control of tunnel construction organization to cope with the features of diversification and complexity. Thus, at the preliminary stage and during the construction of Yuelongmen Tunnel, scientific technologies for dynamic control and management methodologies have been established. Especially, scientific research and integrated innovation based on the existing achievements have been performed in respect of large deformation of soft rock, crossing active fault zone, geological prediction of water-rich karst, ventilation of super long tunnel and logistics organization and transportation. Such studies and innovations have been gradually improved and optimized in the implementation process, which makes the work progress of Yuelongmen Tunnel controllable and effective, and thus provide a useful reference for the construction of similar super long and complex tunnel projects in future.

Key words: Yuelongmen Tunnel of Chengdu-Lanzhou Railway, dynamic construction, construction organization, dynamic control