GaoliGongshan Tunnel-The Longest Railway Tunnel in China

Gaoligongshan Tunnel or Gaoligong Mountain Rail Tunnel (Chinese: 高黎贡山隧道) is a tunnel between Nujiang Station and Longling Station on Dali–Ruili railway in Yunnan, China. It crosses through the whole territory of Longling County and then into Mangshi. Gaoligongshan Tunnel is the key project of Yunnan–Burma railway between Dali and Ruili. The length of tunnel is 34.586 km, it makes Gaoligongshan Tunnel to be the longest single-track railway tunnel under construction in China, also is the longest mountain railway tunnel of Asia and the 7th longest tunnel of the world.

Gaoligongshan Tunnel start construction at 1 December 2015, the planned date of completion at 31 May 2022, the total contract cost is 3.628 million Yuan. The tunnel boring machine “Colorful Cloud No.1″(Chinese: 彩云一号) start work on 28 August 2017, it marked the tunnel entering the comprehensive construction phase.

The Gaoligong Mountain Tunnel (高黎贡山隧道) is located in Longling County, Baoshan City, Yunnan Province, China. It is a key part of the Dali-Ruili Railway, designed for speeds of up to 140 km/h. This tunnel spans a remarkable length of 34.538 kilometers, making it one of the longest railway tunnels in the world. Once completed, it will become the longest railway tunnel in Asia and China.

The tunnel cuts through the Gaoligong Mountain on the west bank of the Nujiang River, in the far western part of the Hengduan Mountain Range (横断山脉).

Construction Timeline

  • End of 2015: The construction of the Gaoligong Mountain Tunnel began as a vital segment of the Dali-Ruili Railway.
  • November 24, 2017: The Robbins tunneling machine was introduced for the guide tunnel construction, which progressed until April 22, 2018.
  • February 1, 2018: The Caiyunhao (彩云号) hard rock tunneling machine started working on the main tunnel, achieving smooth progress.
  • September 27, 2019: The first vertical shaft reached a depth of 762.59 meters, breaking a record for the deepest railway vertical shaft in China.
  • May 20, 2020: The second vertical shaft reached a depth of 640.36 meters.
  • July 2022: The main tunnel construction reached 16.71 kilometers, covering nearly half the total length.
  • December 1, 2023: Full-scale construction moved to regular operations.
  • May 28, 2024: The Caiyunhao and other machines completed the first section of the main tunnel lining.
  • October 5, 2024: The underground mixing station for the tunnel was completed.

Geographic Location

The Gaoligong Mountain Tunnel is located on the west bank of the Nujiang River within the Hengduan Mountain Range. It stretches 34.5 kilometers through the rugged terrain of the Gaoligong Mountain.

Design and Construction

The tunnel is one of the most complex engineering feats in China, spanning 34.5 kilometers and incorporating one inclined shaft and two vertical shafts. These shafts are key to the construction process:

  • The inclined shafts are 3850 meters and 3870 meters long, making them the longest of their kind in China.
  • The first vertical shaft is 762.59 meters deep, and the second is 640.36 meters deep, setting a record for the deepest railway vertical shafts in China.

Two major tunneling machines, the TBM (Tunnel Boring Machines), played a critical role in advancing construction.

Geological and Environmental Challenges

The Gaoligong Mountain Tunnel passes through challenging geological conditions, including:

  • 18 different rock formations and 19 fault zones, creating technical challenges.
  • High geothermal energy with temperatures reaching 102°C in some areas.
  • High ground stress, with the tunnel being 1155 meters underground in places.
  • Active seismic activity in a region affected by the Indian and Eurasian tectonic plates.

Construction and Technological Features

The tunnel has become a testing ground for new technology:

  • The use of Caiyunhao and Caiyun 1 tunneling machines has significantly improved construction efficiency.
  • Advanced mechanized systems have streamlined the drilling, blasting, and concrete pouring processes.
  • Record-breaking achievements in vertical shaft construction, such as the 762.59-meter deep vertical shaft, have demonstrated the tunnel’s engineering prowess.

Significance

The Gaoligong Mountain Tunnel will not only be one of the longest and deepest railway tunnels in the world but will also dramatically improve transportation in southwest China. Upon completion, travel between Dali and Ruili will be reduced from 6-7 hours to about 3 hours. The tunnel is crucial for the China-Myanmar International Railway, enhancing bilateral trade and fostering regional development.

The Gaoligong Mountain Tunnel stands as a major milestone in railway engineering, contributing to China’s infrastructure and international connectivity.