MUANG NGA, Laos, Sept. 22 (Xinhua) -- A Chinese railway engineering company on Tuesday drilled through the Ban Phoukeu Tunnel, the last major long tunnel of nearly 9,000 meters along the China-Laos Railway.
It marked an important milestone in the construction of the cross-border railway, and laid a solid foundation for the timely completion of the mega project.
The Ban Phoukeu Tunnel, with a length of 8,936 meters, is among the 10 major tunnels longer than 5 km along the China-Laos Railway. It is also the fourth longest tunnel with high construction risks, and a bottleneck project along the railway.
The tunnel in Muang Nga of Oudomxay Province, some 400 km north of the Lao capital Vientiane, is located on the geological suture zone. The tunnel crosses seven faults, with extremely complicated geological conditions, which brings difficulties and high risks in construction.
According to He Xinglong, the project manager of the Kunming Branch of China Railway No. 8 Engineering Group (CREC-8 Kunming Branch) undertaking the construction, the average daily water inflow amounted to more than 60,000 cubic meters during the water inrush period, which can fill more than 25 standard swimming pools each day; the gushing water can spray 25 meters far from the advanced deepened explosive hole of the tunnel construction work face.
According to the introduction of the Laos-China Railway Co. Ltd., a joint venture based in Vientiane responsible for the construction and operation of the China-Laos railway, in order to fully promote the construction of the China-Laos Railway, the project team has scientifically organized, strictly managed, and finely carried out the tunnel construction.
During the tunnel construction, the CREC-8 project management strictly adhered to the construction principles like "strong support, fast closure and frequent surveying", to successfully traverse the shallow depth sections, weak rock sections and multiple faults, and managed to overcome work face collapse, water and mud inrush, high water inrush pressure, deformation of soft rock, high ground temperature and rock burst.
In particular, in order to effectively minimize the impact of water gushing on tunnel construction, the project branch installed reverse-slope drainage cables, reverse-slope drainage pumping stations, and drainage pipes for drainage operations at the construction site.
The CREC-8 project management has been fully implementing the COVID-19 prevention and control policies promulgated by the Chinese and Lao governments, and the corporate's overseas epidemic precaution requirements, handling both epidemic prevention and engineering construction at the same time, and sparing no effort in overcoming the shortage of personnel and material supply to ensure tunnel construction.
The CREC-8 has employed 174 Lao workers, and a 32-year-old Lao worker, Somlith Mitdavong, is one of them.
After the Ban Phoukeu Tunnel was drilled through on Tuesday, Somlith told Xinhua emotionally: "I am extremely proud to participate in the construction of the Laos-China Railway. I am very excited to witness the completion of the tunnel I participated in today. My family are all looking forward to the railway's opening to traffic."
"The transportation will be convenient and the future days are more hopeful. I have made many friends from China coming to build the railway. We are colleagues and family," he said.
"When I came to the construction site, I did not know engineering. The Chinese project team then arranged skilled masters to teach me over and over again. Now I can do steel reinforcement and support formwork. When the railway is completed, I will teach others the skills I learned on the construction site, to learn to live a good life on craftsmanship!"
There are 75 tunnels with a total length of 198 km along the China-Laos Railway, of which 10 are major long tunnels with lengths over 5 km. The Boten Tunnel with a total length of 6,453.5 meters, holed through by CREC-5 in March 2019, is the first completed major long tunnel of the project.
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 422-km railway will run from Boten border gate in northern Laos, bordering China, to Vientiane with an operating speed of 160 km per hour.
The electrified passenger and cargo railway is built with the full application of Chinese management and technical standards.
The project started in December 2016 and is scheduled to be completed and operational in December 2021.