Bayu tunnel in Lalin section of Sichuan Tibet Railway
Bayu tunnel, a key control project of Lhasa Linzhi section of Sichuan Tibet railway and listed as a first-class high-risk tunnel, was successfully completed on February 2, laying a solid foundation for the realization of opening to traffic of Lhasa Linzhi section of Sichuan Tibet Railway in 2021
it is reported that the total length of Lalin section of Sichuan Tibet railway is 435.48 km, which is another "Heaven Road" on the snow capped plateau. At present, it has entered a critical period of construction. The main tunnel of Bayu tunnel has a total length of 13073 meters, the horizontal guide has a total length of 9481 meters, the highest altitude is about 3500 meters, the maximum buried depth is 2080 meters, and the highest temperature is about 47 degrees Celsius, of which 94% is located in the rock burst area. In the rock mass of the tunnel, a strong ground stress is accumulated and a heavy rock burst is formed. When rock burst occurs, the stone will be ejected from the wall and roof of the tunnel, "flying like a shell", which is very dangerous
"the rock burst in Bayu tunnel is of high intensity and high frequency. Generally, the rock burst lasts for 2 to 6 hours, and lasts for more than a week at most. Even a few months after the rock burst, there will be a second rock burst, which is very rare in the world tunnel construction history." Qiao Zhibin, the director of Bayu tunnel project, said that the tunnel was safe only after the builders defeated thousands of rockburst threats. At present, the tunnel has set a record of 7015 meters of single head driving in plateau railway tunnel In order to effectively respond to rock burst, the builders, together with the Chinese Academy of Sciences, conducted in-depth analysis and Research on the ground stress, rock burst grade, rock burst warning and prevention in front of the tunnel, established a rock burst warning, prediction and observation platform covering microseismic monitoring, ground stress detection and advance geological prediction, and invented the dynamic layout technology of microseismic sensor array to track rock burst.