VIENTIANE, Oct. 21 (Xinhua) -- The engineers are busy making the final touches to the China-Laos Railway's Friendship Tunnel, the cross-border tunnel connecting Mohan in southwestern China's Yunnan Province and Boten in northern Laos, as the railway is set to start operation in December.
The tunnel, with a total length of 9,595 meters including 2,425 meters belonging to the Lao section, has been named Friendship Tunnel to demonstrate the traditional friendship between China and Laos.
During the construction, carried out by China Railway No. 2 Engineering Group (CREC-2), a pair of mentor and protege drilled respectively from each side of the tunnel and competed in progresses and quality.
Pan Fuping, the mentor aged 50, led a team drilling the tunnel from the Chinese side, while Bai Xiaoke, Pan's protege in CREC-2, holed the tunnel from the Lao side.
After nearly 30 years of front-line work, Pan has been used to living in the wild while working in the tunnels and along the rivers. On a normal working day at 5:00 a.m., he wears his mask, helmet, reflective vest, waterproof shoes, carries a flashlight and goes to check the work in the tunnel.
Bai was confronted with a big trouble. In the depth of the mountains in northern Laos, the tunnel meets a salt layer with a thickness of over 100 meters and a salinity of over 80 percent, a rare situation that was extremely challenging to the safety of the tunnel structure.
Huang Hong, the general manager of the CREC China-Laos Railway Project Headquarters in Vientiane, told Xinhua earlier this month that the salt layer situation in the Friendship Tunnel was the first of its kind in global engineering and had never been encountered by any other construction team before.
"However, with the joint efforts by the CREC-2 and Chinese scientific research institutions, the difficulty was finally removed," he said.
"Salt absorbs water, then dissolves or crystallizes, and the crystallization expands, which has a squeeze effect on our structure. Once the salt layer dissolves, there will also be holes which can cause the structure to sink, and is very harmful to the whole structure," Bai said.
In order to ensure the progress of the project, Bai not only consulted experts, but also studied the situation himself. "With no experience for reference, we do our own research," he told his colleagues.
Surely, Bai's research team included his mentor Pan. During the construction, Pan and Bai made video calls from time to time to update each other on their engineering progress and discussed the problems they encountered.
In September 2020, after over 1,500 days of hard work by more than 1,200 Chinese and Lao engineers, the Friendship Tunnel was successfully bored, laying a solid foundation for the opening of the China-Laos Railway.
Due to the COVID-19 restrictions, Pan and Bai were not able to give each other a bear hug on the day.
"It is something of a pity, but it is all right, the hugs we owed each can be made in the train when the China-Laos Railway is put into operation," Pan told Bai in a recent video chat.
However, even this expectation will not be realized. "I have just come to Tibet to join the Sichuan-Tibet Railway construction," Bai replied.
Bai told reporters that his mentor only told him to "continue to do a good job."
"It is not only his wish, but also his admiration for me, since he must be longing to join me on the plateau (for the construction)."
"The naming of the Friendship Tunnel symbolizes the profound friendship between the two peoples (of China and Laos)," Wang Xiaodong, executive manager of the CREC-2 Friendship Tunnel Project, told Xinhua on Monday.
"To build the China-Laos Railway into a landmark project of the Belt and Road Initiative and of the China-Laos friendship has long been the consensus of our builders with CREC-2, with Bai Xiaoke and his mentor no exception," said Wang.
The China-Laos Railway is a docking project between the China-proposed Belt and Road Initiative and Laos' strategy to convert itself from a landlocked country to a land-linked hub.
The electrified passenger and cargo railway is built with the full application of Chinese management and technical standards. The construction of the project started in December 2016 and is scheduled to be completed and open to traffic in December 2021.