On March 31, 2022, the control project of the Guangxi section of the Guinan high-speed railway, the 10,130-meter-long Yongxing No. 1 tunnel, which was constructed by the Fifth Company of the China Railway 14th Bureau, passed through safely, marking the first high-speed railway in Guangxi with a design speed of 350 kilometers per hour. A breakthrough was made in construction.

Pass through 77 caves

The Yongxing No. 1 Tunnel of Guinan High-speed Railway is located in Hechi, Guangxi, spanning Jinchengjiang District and Huanjiang Maonan Autonomous County. The tunnel site area is a typical karst landform with strong karst development. It passes through 77 karst caves and 3 fault fracture zones. The karst caves reveal The rate is the highest on the whole line, and the risks of water inrush, landslide and deformation are extremely high.

Since the start of construction in August 2018, China Railway 14th Bureau Group has established the research topic of "Key Technologies for Green and Environmental Protection and Rapid Construction of Long Tunnels under Complex Karst Geological Conditions in Southwest China", and has invested 100 sets of large-scale tooling equipment and more than 600 construction personnel. Namely, the 6 working faces will be promoted simultaneously during peak hours.

"The large-scale mud intrusion with a mud inrush of more than 8,000 square meters and the subsequent unfavorable geological sections with a continuous length of more than 800 meters have tested our tunnel construction capabilities." According to the Guinan High-speed Railway Project Department of the China Railway 14th Bureau Manager Wang Baojun introduced.

In the process of tunnel construction, the project department applied new technology and new technology to reinforce the bad geology in the tunnel, overcome the industry problems such as tunnel karst mud intrusion and poor stability of surrounding rock, and achieved the goal of zero accident. At the same time, the project adopts the method of "pile foundation + raft" to traverse harmful geology to reduce the hidden danger of uneven settlement caused by karst geology after operation.

260,000 cubic meters of water in a single day

The underground water of the tunnel body is developed, and it is a water-rich tunnel. The daily water volume is up to 260,000 cubic meters. After conversion, it can fill a standard swimming pool in 7 minutes. It is very difficult and dangerous to discharge water.

In the face of huge water inflow, the project department changed "water control" to "pipe water", built 26 water collection corridors in the tunnel to ensure smooth water flow, and built a drainage tunnel parallel to the tunnel to meet the needs of construction and operation. Drainage needs.

Builders compose a song of ice and fire

The extra-long tunnel is poorly ventilated and the temperature inside the tunnel is high, with a maximum temperature of 40°C in summer. The project department innovatively adopts tunnel ventilation to enhance ventilation effect and improve air quality.

Zhou Haitao, secretary of the project party branch, said: "In order to prevent workers from heat stroke, we use containers to transport 15 tons of ice into the cave every day, distribute them near the construction site and beside the air inlet of the fan, blow cool air to the palm face, and at the same time pass Road spraying and other methods to improve the construction work environment”.

Focus on scientific and technological breakthroughs

 For more than three years, the project department has given full play to the leading role of scientific and technological innovation in engineering construction, continuously tackled key problems in science and technology, innovated technological methods, and actively promoted the transformation of scientific and technological achievements. At present, it has obtained 6 utility model patents, formed 3 scientific research reports, and published papers. And 16 construction methods, the project QC team won the excellent QC team of the China Construction Association, and realized the combination of "production, learning, research and application".

The Guinan high-speed railway has a total length of 481 kilometers and is an important part of the Baotou-Haikou channel, the main channel of the national "eight vertical and eight horizontal" high-speed railway. After the completion and opening to traffic, the travel time from Nanning to Guiyang will be shortened from the current 5 hours to about 2 hours, which is of great significance to promoting the deep integration of transportation, logistics, commerce and industry of the two provinces and regions of Guizhou and Guizhou. Editor/Ma Xue