On July 3, the "Wensu" TBM at the main-line exit portal of the West Tianshan Extra-Long Tunnel—the world's deepest-buried large-cross-section highway tunnel and China's first highway tunnel to pass directly beneath a glacier, built with the participation of CCCC First Highway Engineering Group—was successfully launched, marking that construction of the West Tianshan Extra-Long Tunnel has entered a critical phase.

The "Wensu" TBM was successfully launched.

The West Tianshan Extra-Long Tunnel, with a total length of 15.7 km and a maximum burial depth of 2,365 m, is the controlling project of the Zhaosu–Wensu Highway Project on the G219 line. The tunnel is located on the southern slope of the West Tianshan, an area characterized by severe cold, high latitude, high altitude and high seismic intensity, where the average temperature in the coldest month is below minus 23 degrees Celsius and the tunnel site is covered by ice and snow all year round.

To meet the ventilation and smoke-exhaust requirements during tunnel construction and operation, the West Tianshan Extra-Long Tunnel innovatively adopts the "main tunnel + side pilot tunnel" construction technique. This is also the first Class-I highway tunnel in China over 10 km long to use a side pilot tunnel as a ventilation shaft. The technique takes advantage of the advance excavation of the TBM hard-rock boring machine, reasonably opens cross passages and increases the working faces of the main tunnel, thereby achieving "short construction of a long tunnel."

The tunnel adopts the construction method of "main tunnel (drill-and-blast) + side pilot tunnel (drill-and-blast + TBM)", making it the first Class-I highway tunnel in China over 10 km long to use a side pilot tunnel for ventilation and smoke exhaust. The "Wensu" TBM hard-rock boring machine used for the side pilot tunnel construction was independently developed by CCCC Tianhe, with a length of 235 m, a weight of 1,800 t and a diameter of 8.83 m; it is the largest open-type TBM hard-rock boring machine crossing the Tianshan Mountains. The TBM applied in the West Tianshan Tunnel has also been innovatively improved, with the addition of a series of cutting-edge systems and equipment such as a steel-bar row system, an integrated excavator and mucking belt conveyor, and large-scale refrigeration equipment, and is equipped with a CFC advanced water exploration system, an SHP rockburst detection system, an advanced geological prediction system and a multifunctional advanced detection drilling rig, further ensuring excavation safety.

The West Tianshan Extra-Long Tunnel is located in Wensu County, Aksu Prefecture, which has been a shining pearl on the Silk Road since ancient times. The "Pearl of the Silk Road" pattern painted on the cutterhead of the "Wensu" highlights the regional cultural characteristics of Xinjiang.

After the Zhaowen Highway on the G219 line is completed, the highway distance from Yining City to Aksu City in Xinjiang will be shortened from the current 1,710 km to 500 km, which is of great significance for promoting the economic development of northern and southern Xinjiang and safeguarding Xinjiang's social stability and long-term peace and order.