The Dalong No 2 tunnel of the China-Laos Railway being built by Sinohydro Bureau 3 Co, a subsidiary of POWERCHINA, was drilled through successfully on March 28.
This is the third tunnel to complete drilling during the novel coronavirus pneumonia epidemic.
The Dalong No 2 tunnel of the China-Laos Railway is drilled through. [Photo/POWERCHINA]
The tunnel, which is located in Luang Prabang Province in Laos, has a design speed of 160 kilometers per hour and is 2,321 meters long.
Officials said the tunnel area is a structurally eroded alpine landform with large terrain relief and a relative height difference of more than 100 m. The formation lithology is mainly Carboniferous slate with sandstone, marlstone and limestone slate, with developed joint fissures and a broken rock mass, making it difficult to execute the construction.
Since its construction in May 2017, the project department overcame the difficulties posed by the narrow construction site, tight construction period and difficult transportation of materials and materials during the rainy season.
The company continued to work on optimizing the construction plan and achieved zero accidents, maintaining the safety and quality of the tunnel construction.
Officials said that in the face of the severe coronavirus epidemic in the world, the project's managers focused on epidemic prevention and control measures while ensuring its ultimate completion.
The No 1 tunnel of Shanene Mountain drilled through smoothly on Feb 10 and the Dalong No 1 tunnel completed drilling on Feb 22, they added.