9 years of hard work! Construction of Haba Snow Mountain Tunnel on Yunnan Tibet Railway Completed
On the morning of July 8, the construction of the last section of ballastless track bed of Haba Snow Mountain Tunnel was completed, marking the completion of the last tunnel of Lijiang Shangri La section of Yunnan Tibet Railway after nine years of hard construction. At this point, the construction of all 20 tunnels in the Lixiang section has been completed, and the long track laying phase has been shifted, creating favorable conditions for the opening and operation of the tunnel within the year.
This project prioritizes excavation of the pilot tunnel to effectively release ground stress. It refers to digging a hole slightly smaller than the normal section at the main tunnel position, allowing the ground stress to be released before expanding to the main tunnel section. Generally, only one layer of initial support is required for the tunnel, while the Haba Snow Mountain Tunnel uses three layers of initial support. At the same time, 108 mm diameter large locking foot anchor pipe is used, 76 mm tensile anchor pipe is added at the tunnel bottom, three-dimensional reinforcement is added in the inverted arch filling, and a 60 mm buffer layer is added between the initial support and the secondary lining to ensure the safe tunneling.
Haba Snow Mountain Tunnel is located in Dêqên Tibetan Autonomous Prefecture, Yunnan Province, with a total length of 9.5 kilometers and a maximum buried depth of 1155 meters. It is a first-class high-risk tunnel and a key and difficult control project along the whole line. The tunnel is located at the southeast edge of the Qinghai Tibet Plateau. The middle section of Hengduan Mountains and deep mountain canyons have obvious geomorphic characteristics. Affected by high ground stress, plate tectonic compression, and Fracture zone activities, geological problems such as large deformation of soft rock during construction are extremely prominent.