The Laohukou Pass on the 216 National Highway, 4280 meters above sea level, is called the "dead road section" by the locals. There are no less than 100 vehicles buried here. Today, the 22-kilometer-long Tianshan Shengli Tunnel, the longest road tunnel in the world, is passing through millions of years of dust and mud in the mountain more than 1,000 meters below the Laohukou. The victory of TBM, built according to the terrain conditions of the Tianshan Mountains, is a miracle. This is the world's first new type of hard rock roadheader using pressure grouting. The cutter head has a diameter of 8.43 meters, close to the height of a three-story building, and can traverse various complex geological layers. How difficult is it to get through such a super tunnel?

weight! The maximum soil stress value is 21.8 MPa, which is equivalent to 1 cm2 of rock bearing a weight of 218 kg, which is more than 50 times higher than the general rock bearing capacity, which means that rock bursts are likely to occur during construction, and the destructive force is equivalent to 4- A magnitude 5 earthquake.

cold! The tunnel site is located in a high-cold and high-altitude area, with an average annual temperature of -5.4 degrees Celsius and a minimum temperature of -41.5 degrees Celsius. Even if the country enters the hot summer in June, there is still heavy snow here, which puts a severe test on construction efficiency.

deep! The maximum buried depth of the tunnel is 1112.66 meters. The greater the burial depth, the higher the probability of rock bursts, large deformations of soft rocks, high ground temperature, and high-pressure water gushing. In Tianshan, the No. 2 shaft of the Shengli Tunnel is 702 meters deep, which is the deepest road tunnel shaft in China. If this long chimney is taken out, it will be 100 meters higher than the "small waist" of the Guangzhou Tower.

high! The highest elevation of the shaft is 3623 meters, and altitude sickness may occur above 3000 meters. Coupled with the extreme low temperature, not only the workers, but also the efficiency of construction machinery will be greatly reduced. Editor/Tian Zengpeng