Chinese construction teams tasked with digging a tunnel through one of the world’s longest mountain ranges have begun the most difficult part of the megaproject: cutting under several kilometers of glaciers.
Construction teams deployed a domestically-made tunnel boring machine (TBM) on Wednesday to dig under the giant glacier to build the main passage of the tunnel, state news agency Xinhua reported.
The 1,800-ton rig, named Wenju, was designed and built by state-owned China Communications Construction Corp. It is 235 meters (771 feet) long and has a diameter of 8.83 meters, making it the widest rig currently being used in any tunnel-boring project in the Tianshan region, according to the Communist Party newspaper People’s Daily.
The Tian Shan mountain range stretches 2,500 km across Central Asia, between Kyrgyzstan, Uzbekistan and Kazakhstan, about two-thirds of which is in the Xinjiang Uyghur Autonomous Region. Its average elevation is about 4,000 metres (more than 13,000 feet).
The Western Tianshan Tunnel will be China’s first straight tunnel carved under a glacier, with more than three-quarters of it – about 12 km – passing through rock beneath 1 km of ice, with some sections passing under 2.4 km of ice.
Wenshu is also the most advanced tunnel-boring machine to cross the Tianshan mountain range, an earthquake-prone region with average winter temperatures of minus 23 degrees Celsius (minus 10 degrees Fahrenheit). The region’s geological conditions pose unique safety and environmental challenges for tunneling, including water intrusion, rock splashes and fluctuating surface temperatures, Xinhua reported in April.
Construction of the tunnel began in September last year and is scheduled to be completed in 2026. The project will be the most important section of the 237-km Zhaosu-Wansu Expressway (G219), linking Zhaosu county in the north and Wensu county in the south of the Xinjiang Uygur Autonomous Region, according to the People’s Daily.
Due to open in 2027, the highway will be part of a major transport route connecting China with Russia, Kazakhstan, Tajikistan, Kyrgyzstan and Pakistan, as well as a key link between Xinjiang and Tibet.
When the expressway opens at the end of next year, the 22.1-kilometer tunnel will be the longest in the world.
