[Explanation] After 1036 days of unremitting struggle, on August 10, China's northernmost high-speed railway-the last tunnel of the Mujia High-speed Railway, the Junshan Tunnel was successfully completed. So far, the foundation and bridge erection of Mu-Jia Gao railway have been completed, laying the foundation for the completion of the Mu-Jia high-speed railway before the end of the year.

  [Concurrent] Zhou Huanhuan, Chief Engineer of Mujia High-speed Railway Eight Standard Project Department

  After the tunnel is safely penetrated, the first and most important thing we need to do is to measure the tunnel. After our actual measurement, the penetration error is 2.1 cm, which can fully meet the requirements of our acceptance standards and also ensure the construction progress of the remaining tunnel projects.

  [Explanation] Mujia High-speed Railway is located in the high-cold area. The frost-free period of the year is only 140 days. The average temperature in winter is -19℃ and the lowest temperature is -35℃. The long-term low temperature and severe cold have brought great challenges to the construction of high-speed rail. Since the start of construction in November 2016, the construction unit has built construction access roads on the swamp to ensure the quality of concrete pouring in the extremely cold environment, and applied new equipment and new techniques to overcome many construction problems.

  [Concurrent] Zhou Huanhuan, Chief Engineer of Mujia High-speed Railway Eight Standard Project Department

  There are two main difficulties in the construction process. The first difficulty is that our Mujia high-speed railway is located in the severely cold northeast area, and the effective construction period is short. In winter, we conduct comprehensive heat preservation in the mixing station, steel structure processing plant and tunnel. Effective use of winter construction time has greatly improved our construction schedule. The second difficulty is that during the construction of the tunnel, we found that the dangerous rock changes very quickly. We made full use of the advanced geological forecasting methods, adhering to the construction concept of rock change and self change, and strengthened construction control to ensure the safe passage of the tunnel.

  [Explanation] It is understood that the Mujia high-speed railway has a total length of more than 370 kilometers and a design speed of 250 kilometers per hour. It is one of the construction projects of China's "Medium and Long-term Railway Network Planning" and a key railway project of China's "13th Five-Year Plan". The Mujia Passenger Dedicated Terminal is located in Jiamusi, a frontier city open to Russia, only 180 kilometers away from the Sino-Russian border.

  [Concurrent] Zhou Huanhuan, Chief Engineer of Mujia High-speed Railway Eight Standard Project Department

  The completion of the Junshan Tunnel marks the completion of the entire Mujia (high-speed rail) line. The next step is to carry out ballastless track construction. It is expected that the entire Mujia line can be opened for operation in the second half of next year.

  Reporter Wei Lai reports from Shuangyashan in Heilongjiang

Editor in charge: [Li Yuxin]