[Explanation] After 4 years of hard work, the Guiyang-Nanning high-speed railway Jiuwandashan No. 4 tunnel was safely completed on August 17.

So far, all tunnels on the Guinan high-speed rail line have been completed, laying the foundation for the opening of the line.

  [Explanation] Song Shibin lives in Shiyan City, Hubei Province.

He came to Jiuwandashan No. 4 tunnel to participate in the construction in March 2018, and only returned home twice during the Spring Festival. In the past four years, he has spent less than 20 days at home.

In order to complete the construction as scheduled, Song Shibin sometimes spends more than 12 hours a day in the tunnel.

  [Same period] Song Shibin, leader of the excavation team at the exit of the No. 4 tunnel in Jiuwandashan, Guinan high-speed railway

  To be honest, we have been here for a few years. The measurement tells us how many meters there are. We are all looking forward to this day, and we are very happy. After four or five years, who is unhappy that we will pass through? no.

  [Explanation] Guinan High-speed Railway Jiuwandashan No. 4 Tunnel is located in Huanjiang Maonan Autonomous County, Guangxi. The tunnel is 15,485 meters long and passes through 6 faults and geological contact zones. It is the longest railway tunnel in Guangxi and is also the Guangxi section of Guinan High-speed Railway. The longest Class I high risk tunnel.

The Jiuwanda mountain area where the tunnel is located is one of the seven world natural heritage areas in the "Southern China Karst" and can be called the "Karst Karst Geology Museum". The geological conditions are extremely complex and the construction is extremely difficult.

  [Concurrent] Xue Xiping, Project Manager of Guinan High-speed Railway Project Department of China Railway 18th Bureau

  The tunnel exit geology is "carbonaceous shale slow-dipping stratum". This shale structure is very unstable. Using normal drilling and blasting methods, after the rock stratum is shaken, it is easy to fall off in one piece, easily causing landslides and affecting construction. Safety.

We can only use rock drills and excavators to dig one bucket, one inch by one inch, and we can only excavate 45 cm and 682 meters of broken rock every day. We dug for a full 22 months, which is very rare in the process of tunnel construction.

  [Explanation] The entire Guinan high-speed rail line has to pass through 108 tunnels, of which the Jiuwandashan tunnel group is the most difficult to construct.

The tunnel group consists of No. 1, 2, 3 and 4 tunnels in Jiuwandashan, with a total length of 41,459 meters.

Jiuwandashan No. 2, 3 and 4 tunnels are located in the Huanjiang Maonan Autonomous County of Guangxi, with a total of 24,447 meters, which is the largest tunnel community on the whole line.

After all the tunnels are completed, the Guinan high-speed railway will enter the track laying stage.

On the morning of August 16, the Guinan high-speed railway began to implement track laying operations on the Longjiang double-track super bridge in Hechi City, Guangxi. It is expected that the Guangxi section of the Guinan high-speed railway will be completed by the end of this year.

  [Explanation] The Guinan high-speed railway runs through the northwest of Guangxi and the southeast of Guizhou. It is the first high-speed railway in Guangxi with a design speed of 350 kilometers per hour. The whole line is expected to open at the end of 2023. At that time, the operation time from Nanning to Guiyang will be shortened from the original more than 5 hours to about 2 hours.

  [Explanation] After completion, the Guinan high-speed railway will form a complete railway transportation network in southwest China together with the Chengdu-Guiyang high-speed railway, the Guiyang-Guangzhou high-speed railway, and the Nanning-Kunming high-speed railway.

After the Guinan high-speed railway connects Nanning to Pingxiang, it will make Southwest China more convenient to connect with ASEAN countries.

  Jiang Xuelin and Wang Yizhao reported by Nan Yufeng in Hechi, Guangxi

Responsible editor: [Lu Yan]