China News Agency, Xishuangbanna, April 19 (Zhang Weiming, Li Juntao) The Jingkuan No. 2 tunnel of the Yu (Xi) Mo (Han) section of the China-Laos railway under construction was opened on the 19th. This is the first super-large cross-section tunnel across the China-Laos railway , Marking a major breakthrough in the construction of the Yumo section of the China-Laos Railway.
Jingkuan No. 2 Tunnel is located in Jinghong City, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province, with a total length of 4.6 kilometers. The tunnel is adjacent to the Lancang River. The exit structure changes from double to third line and then to single line. The maximum cross-section is 249 square meters, which is three points larger than the general double-line tunnel. First, the rest are single-line tunnels. The surrounding rock is broken and fissures are developed. It is very easy to soften in water. It passes through the shallow burial section many times. The minimum depth of the tunnel is only 10 meters, which makes the construction difficult.
"The design of the super-large section is mainly to reserve the connection conditions for the expansion of the new line in the future. When the junction is branched, a new railway line can be built. Excavation of the super-large section in the broken surrounding rock is easy to collapse, deformation and settlement. We adopted a four-step construction process to increase the locking feet, divided the section into several small units, and finely organized it to ensure that the tunnel was connected as scheduled. "Said Wang Guanying, manager of the Yumo Railway Project Department of the China Railway 22nd Bureau Group.
At present, the cumulative investment of the Yumo section of the China-Laos Railway is 38.45 billion yuan, 76% of the design volume, more than 67 million cubic meters of earth and stone for the subgrade, and more than 80% of the construction of extra large bridges and tunnels.
The China-Laos Railway under construction is the first international railway with the Chinese side investing in the construction, adopting Chinese technical standards throughout the line, using Chinese equipment and directly connecting with the Chinese railway network after the proposal of the “Belt and Road” initiative. After opening to traffic, it will become another international railway channel for entry and exit in Southwest China. By then, China's Kunming to Laos, Vientiane, is expected to achieve the evening. (Finish)