The Ganzhuang Tunnel, the first high-risk tunnel more than 15 kilometers in length on the China-Laos Railway, was completed on May 24, eight days ahead of schedule.
A part of the Kunming-Vientiane section of the China-Laos Railway, the tunnel is contracted by China Railway 17th Bureau Group Co., Ltd., a subsidiary of China Railway Construction Corporation Limited.
Located in Yuanjiang county of Yuxi in Southwest China's Yunnan province, the tunnel has a buried depth of 860 meters and was dug through eight faults. Complicated geological conditions like karst, underground rivers, noxious gas, special rock and soil and silty clay added to the engineering difficulties.
Workers set up 4 parallel adits and 4 inclined shafts in 6 construction sites during the engineering, separating the long tunnel into several parts.
The entrance and exit of the tunnel have a height difference of 350 meters, which created a challenge for ventilating and drainage. What's worse is that the tunnel was built in areas with weak surrounding rock and rich water resources, making its construction like digging a hole in a piece of tofu.
The steep slopes also added to the challenges and required an "S" shaped line to be built. Although the tunnel length was extended and the construction became harder because of the "S" line, the height difference of the railway and risks of the later operation were reduced.
Smart technological devices including TEM instrumentation and electromagnetic induction were taken during the construction to detect risk sources like underground water, fault fracture zones and karst caves. A high-level pumping station with 60 large-power pumpers was also set up.
So far, 67 tunnels of the 508-meter Yuxi-Mohan section in Yunnan of the Kunming-Vientiane railway have been completed and installation of rails, bridges and stations is progressing smoothly.
With a designed speed of 160 kilometers per hour, the Yuxi-Mohan section is expected to open to traffic by the end of 2021 simultaneously with the Boten-Vientiane section, the Laotian part of the Kunming-Vientiane railway.
Upon operation, travel time between Kunming and Vientiane will be shortened to within 12 hours.
Workers weld the tunnel. [Photo/sasac.gov.cn]
Exit of the Ganzhuan Tunnel [Photo/sasac.gov.cn]
