Starting from Wensu County, upstream along the Muzhart River, the mountains become steeper and the population decreases. Walking to the foot of Muzhalteda Pass at an altitude of over 2600 meters, an ice peak lies in front of us, and the road ends here. A thousand years ago, this pass known as the Xiata Ancient Road was the most dangerous shortcut from Yili to southern Xinjiang. The caravans of merchants and horses crossed the glaciers, and every further advance could cost their lives. Now, a group of builders have set up camp at the foot of the Ice Peak, aiming to dig a 15.7-kilometer tunnel from the depths of the mountain to turn a thousand year old danger into a path.

Challenge under the Glacier

The West Tianshan Extra Long Tunnel is the throat of the entire line and also the world's first highway tunnel to directly pass through a glacier, with the world's deepest burial depth reaching 2380 meters, equivalent to the height of nearly 800 floors of buildings. The top of the tunnel is directly covered by a permanent glacier. The entire tunnel passes through the Nalati active fault zone, with a 370 meter eroded rock fracture zone distributed along the line. Multiple world-class problems such as rock burst, sudden mud and water influx, and high ground temperature are superimposed and hit. High ground stress compresses hard rocks into springs that can collapse at any time. Small rock bursts sound like brittle sounds, while large and strong rock bursts can last for hours, and rock fragments are ejected without warning; The temperature inside the cave approached 41 degrees Celsius at one point, with an average daily inflow of tens of thousands of cubic meters.

A major country will use heavy weapons to break through the situation

Faced with exam papers without ready-made answers, the project team chose to break through the deadlock with technology: the main tunnel adopted drilling and blasting method, the flat guide tunnel was constructed by domestic hard rock tunneling machines, and two domestic TBMs excavated from the north and south ends facing each other, cutting the long tunnel into short sections and achieving short tunneling. If conventional inclined and vertical shaft schemes are used, dust and exhaust gases may contaminate glaciers and accelerate melting, while the flat tunnel scheme avoids direct disturbance to glaciers. The builders also pioneered the ventilation scheme of the pilot tunnel in China, solved the ventilation problem of the super long tunnel, and developed the foam concrete shock absorption layer technology to deal with the large deformation of the fault, and supported the broken surrounding rock with light steel pipe pieces. Two domestically produced tunneling machines have repeatedly broken the construction records of similar equipment, with daily footage exceeding 60 meters and monthly footage exceeding 800 meters. As of now, the project has applied for a total of 18 invention patents and 26 utility model patents, filling the gap in the construction of deep buried glacier tunnels in China with multiple core technologies.keywords:Engineering infrastructure

The livelihood account behind Tongtu

At present, the main works of the roadbed and bridge have entered the final stage, and the road paving and tunnel excavation are being carried out in a dual track manner. The construction of the retaining wall for the Zhaowen section of Zhongjiao Road has been completed, with a cumulative completion of 95% of the roadbed earthwork; The bridge foundation and substructure are all completed, and the cumulative completion of beam and slab installation is 95%; The cumulative completion of asphalt paving on the road surface is 12 kilometers. In the 6.8-kilometer tunnel task undertaken by this section, the left tunnel has been excavated for 4.8 kilometers and the right tunnel for 4.1 kilometers, and the three working areas of the left tunnel have been connected. The Zhaowen Highway, with a total length of about 232 kilometers, runs along the Millennium Summer Pagoda Ancient Road, connecting snow capped mountains, glaciers, forests, grasslands, and river valleys in Yadan. It is the second tourism corridor that connects the north and south of Xinjiang after the Duku Highway, and is not affected by ice and snow blocking mountains, allowing for all-weather travel throughout the year. By 2027, the entire line will be fully connected, and the beef and mutton, rapeseed oil, walnuts, and apples of Zhaosu and Wensu will be able to be transported to each other year-round. The development of cultural and tourism resources along the route and the export of characteristic agricultural and animal husbandry products will also be activated, injecting new momentum into the development of county-level economy and rural revitalization.Editor/Yang Meiling