The Guigala Tunnel is the control project of the Tibet S5 Line Lhasa-Shannan Expressway Project, and is currently the longest ultra-high-altitude highway tunnel in the world. Guila Tunnel has a design speed of 80 kilometers per hour. It is a first-class separated two-hole four-lane highway tunnel. The distance between the two holes is 25-35 meters. The maximum buried depth of the tunnel is about 1152 meters. The total length of the left tunnel is 12798 meters and the total length of the right tunnel is 12790 meters. , the left hole has been successfully completed.

The project will help the Tibet Autonomous Region to promote the construction of one nuclear circle, two belts and three districts. It is a key project for the integrated development of Lhasa and Shannan, and an important part of building a one-hour economic circle from Lhasa to Shannan.

Engineering Features

Height: The average altitude of the tunnel is about 4,300 meters, of which the 1# inclined shaft is 4,560 meters above sea level, high altitude, high cold, hypoxia, large temperature difference between day and night, frequent personnel changes, and low efficiency of equipment and tools.

Length: The main line of the tunnel is 12.8 kilometers long, and ventilation and oxygen supply are difficult; the inclined shaft is long, the longitudinal slope is large, and the cross-section is small, and it is difficult to organize logistics and transport and long-distance reverse slope drainage.

Difficulties: The surrounding rock in the tunnel site area is complex, and there are unfavorable geology such as shallow burial, rich water, bias pressure, rockburst, and high ground stress, and the efficiency is low.

Cold: The construction temperature in winter is low, and starting from September, there is a 5-month low temperature construction period.

The project is located in a plateau area, which belongs to the high cold anoxic area. The difficulty of traditional manual operations increases and the efficiency decreases. Workers cannot work continuously in the cave for more than 4 hours. In order to reduce the number of operators and reduce the labor intensity of workers, the project actively promotes mechanized construction, improves construction efficiency, and speeds up construction progress.

It has successively introduced advanced equipment such as three-arm rock drilling rigs, wet spraying manipulators, waterproof board automatic laying and hanging rigs, and mobile hydraulic trestles; cooperated with Liugong to introduce several plateau electric loaders and electric excavators to ensure work efficiency , to achieve the goal of low-carbon environmental protection.

The Guigala Tunnel is the world's first road tunnel with a length of more than 10 kilometers and all lines are located above 4,000 meters above sea level. Due to the high cold and hypoxia, the oxygen content in the air in the tunnel has dropped to about 20%. , The ventilation effect is poor. In order to solve the problem of ventilation in the cave, the project adopts the roadway ventilation method. Editor / Xie Li