The Friendship Tunnel on the China-Laos Railway, designed by China Railway Eryuan Engineering Group and constructed by China Railway No.2 Engineering Group (CREC-2), was dug through on September 13, marking the completion of 97.5 percent of the designed tunnels in the Chinese part of the railway.
Engineers and workers celebrate the completion of the Friendship Tunnel on the China-Laos Railway.
The China-Laos Railway connects Kunming, capital of southwest China’s Yunnan Province, to Vientiane, capital of Laos. The Friendship Tunnel is the only cross-border tunnel on the railway, measuring 9.59 kilometers in length and with a design speed of 160 km/h.
Entrance to the Friendship Tunnel (Chinese section).
The tunnel lies in a carbonate rock eroded environment, where the high salt content section is 1.7 kilometers long, with a maximum salt content of 80 percent, which is highly corrosive to the tunnel structure. It is rare both at home and abroad for a tunnel to pass through such a high content carbonate rock stratum. Beginning in June 2016, the South Yunnan Railway Construction Command of China Railway Kunming Bureau Group organized the China Railway No.2 Engineering Group, the Academy of Railway Sciences and other organizations to carry out technical research. After 16 months of efforts, the physical strength of concrete finally reached the target requirements in September 2017, thus overcoming the world problem of tunnel construction in a carbonate rock eroded environment. Evaluated by experts, the technology has reached the world’s advanced level. The China-Laos Railway is the first international railroad to be mainly invested by the Chinese side and connected with China’s railway network. After it is completed and opened to traffic, the railway will shorten the travel time between Kunming and Jinghong in Xishuangbanna Dai Autonomous Prefecture to only three hours, and passengers on a night train travelling from Kunming to Vientiane are expected to arrive early in the morning.
