China-Laos railway tunnel's border drilling finished

（Worker's Daily / Photo）

VIENTIANE, May 20 (Xinhua) -- China Railway No. 2 Engineering Group (CREC-2) told Xinhua that it has drilled through the Friendship Tunnel from northern Laos to the border line with China on Wednesday.

After 37 months of hard work, the China-Laos Railway Friendship Tunnel, which runs through the Laos-China border and is constructed by CREC-2 and designed by China Railway Eryuan Engineering Group, was bored from northern Laos' Boten, some 370 km north of Lao capital Vientiane, to the border with China on Wednesday.

The progress has, hence, laid a solid foundation for the completion of the railway by December 2021.

The Friendship Tunnel, with a total length of 9,959 meters and 2,425 meters of which belonging to the Lao section, and with the maximum burial depth of 243 meters, is located in the forests in northern Laos.

（Worker's Daily / Photo）

In the depth of the mountains, the tunnel meets salt layer with thickness of over 100 meters and salinity of over 80 percent, which is extremely harmful to the safety of the tunnel structure.

In view of the poor geological conditions of the tunnel and the frequent occurrence of water inflow and slump, the project department strengthened the geological prediction and information collection. They held several meetings to refine and optimize the construction plan to ensure the safety, quality and progress of the project.

With the COVID-19 epidemic setting in, the Chinese engineering companies also comprehensively implemented epidemic prevention and control to ensure tunnel construction.

The China-Laos Railway is a strategic docking project between the China-proposed Belt and Road Initiative and Laos' strategy to convert from a landlocked country to a land-linked hub.

The 414-km railway, with 198-km tunnels and 62-km bridges, will run from Boten border gate in northern Laos, bordering China, to Vientiane with an operating speed of 160 km per hour.