Recently, deep in the western foothills of the Qinling Mountains, as the last section of the rock wall was chiseled through, a gust of wind rushed in from the other end of the tunnel - the Anhua Tunnel, the longest tunnel on the entire Tianlong Railway, was completed.

A tunnel through Qinling Mountains

The Anhua Tunnel is located between Foya Town and Anhua Town in Wudu District, Longnan City, passing through the Zhongshan District of Qinling Mountains. It is a single tunnel, single track electrified railway tunnel with a total length of 19.98 kilometers and a maximum burial depth of over 700 meters. It is the longest and most difficult control project on the entire Tianlong Railway. It was constructed by Gansu Tianlong Railway Co., Ltd., designed by China Railway First Institute, and participated in by China Railway 16th Bureau and China Railway 18th Bureau.

The completion of this tunnel marks the completion of all 14 tunnels within the 2nd section designed and managed by China Railway First Institute. It also means that all tunnels in Longnan have been completed, freeing up key passages for subsequent track laying, station building construction, and timely completion and operation.

Dealing with Geology

The difficulty of Anhua Tunnel lies in its geology. The tunnel area passes through carbonaceous phyllite and fractured fault zones, where adverse geological conditions such as high ground stress, large deformation of soft rock, and high ground temperature are superimposed, making it a Class I high-risk extra long tunnel.

The technical team takes targeted measures: for the large deformation sections of Grade I and II soft rock, different large deformation lining structures are adopted based on the different rock grades of Grade IV and V. Elliptical lining sections are set, matched with self advancing long anchor rods, and radial grouting of the side walls is strengthened; For the shallow buried section of loess at the entrance of the tunnel, implement advanced support with long pipe sheds and strengthen the protection of the slope at the entrance; Improve special monitoring measures for local radioactive anomalies, conduct waste detection and evaluation, and ensure the compliant use of waste. By stacking up the processes one by one, we finally managed to gnaw off this hard bone.

Southward Passage

Behind the Anhua Tunnel is an astonishing set of numbers. The Tianlong Railway Section 2 is designed and managed by China Railway First Institute. There are a total of 14 tunnels with a total length of 76.676 kilometers, accounting for 73.28% of the total length of the line. There are also 19 supporting tunnels with a total length of 28.734 kilometers. Among them, the 15.385 kilometer Jifengshan Tunnel, 15.032 kilometer Pingluo Tunnel, 19.98 kilometer Anhua Tunnel, and 12.431 kilometer Majie Tunnel are listed as the four major and difficult tunnels.

Faced with challenges such as large tunnel scale, long mileage, parallel construction of multiple high-risk tunnels, and complex geological conditions, the Tianlong Railway EPC Project Department puts control at the forefront: strictly implements advanced geological forecasting and surrounding rock monitoring and measurement, builds an information management platform, relies on real-time monitoring systems, access control systems, and personnel positioning devices, adheres to risk pre prediction, strengthens dynamic closed-loop control of hidden dangers, and continuously optimizes construction organization supported by process innovation and technological empowerment, and comprehensively promotes safety, quality, progress, and environmental and water conservation work.

The Tianlong Railway starts from Tianshui City, Gansu Province in the north and ends in Longnan City in the south. It is a key project determined by the national medium and long-term railway network planning and the railway development plan of Gansu Province. It is also the first fully invested and independently built railway project in Gansu Province, with a total investment of about 24.3 billion yuan and a designed speed of 160 kilometers per hour. It is planned to be completed and opened to traffic by the end of 2027. After the completion of the line, it will be closely connected with the Longhai Railway and the Lanyu Railway, opening up the southern exit channel of Gansu Province and constructing a new channel for transporting coal from the north to the south. It will become an important link to enhance the transportation capacity of the western land sea new channel and connect the Silk Road Economic Belt and the Yangtze River Economic Belt.keywords:Engineering infrastructure

For the Qinba Mountain area, this railway not only connects Tianshui and Longnan, but also provides new possibilities for mineral resources, agricultural products, and convenient travel for the people along the line.Editor/Yang Meiling