Research on concrete pumping to overcome landslides in Chi Thanh tunnel

On the afternoon of May 22, Project Management Board 85 (Ministry of Transport) and Vietnam Railway Corporation inspected the landslide site and conducted geological research to consider and calculate solutions to handle the landslide incident at Chi Thanh railway tunnel, through Chi Thanh town, Tuy An district, Phu Yen.

Here, technical units conducted technical exploration drilling on the DT641 route above the tunnel roof to explore the geology around the area. From there, they considered pumping concrete down to reinforce the tunnel roof and calculated options to overcome the landslide incident in the most effective way.

Technical team drilled geological exploration on DT641 road, above the roof of Chi Thanh tunnel to find a solution.

Mr. Nguyen Thanh Hoai, Director of Project Management Board 85, said that the geology in the Chi Thanh railway tunnel area is complex, unpredictable, and constantly changing, so construction and repair work is facing many difficulties.

"The Board has directed staff and workers to monitor and warn of potential dangers while performing construction, and ensure occupational safety. Through the repair of railway tunnels through the area, it has been shown that most of them are degraded and at high risk of landslides. Therefore, re-evaluating all railway tunnels to have proactive repair plans is extremely necessary," Mr. Hoai shared.

More than 50 officers and workers of Phu Khanh Railway Exploitation Branch, in coordination with the Project Management Board, are continuing to deploy solutions to overcome landslides and rocks at the Chi Thanh railway tunnel. At the scene, workers take turns spraying concrete into landslides in the tunnel to hold back the soil and rocks. At the same time, technical inspections and geological surveys are being conducted to drill rocks from the tunnel roof and then pour concrete to reinforce the landslide sections.

The railway industry is still working hard to fix the landslide in Chi Thanh tunnel. However, the time for the tunnel to be opened is still unknown.

Mr. Le Quang Vinh, Director of Phu Khanh Railway Exploitation Branch, said that the landslide incident at Chi Thanh railway tunnel was considered similar to the landslide at Bai Gio railway tunnel (Khanh Hoa province) that occurred more than a month ago. The soil and rocks on the tunnel roof collapsed, blocking the tunnel and the solution was applied similarly to Bai Gio tunnel.

Accordingly, the construction unit drilled to create anchors at both ends of the collapsed tunnel area. After that, they sprayed concrete to harden and reinforce the tunnel and then organized the clearing of soil and rocks below. Currently, in the Chi Thanh railway tunnel, there are about 200m3 of landslide soil and rocks, blocking the tunnel.

"The unit has focused all its human resources and mobilized many more units in the industry. There is no shortage of human resources. Currently, we are drilling to create anchors to pump concrete back up to the roof of the tunnel to stabilize the geology and prevent further landslides. However, the geology is unstable, water seepage leads to softness, and it is very easy to collapse further," said Mr. Vinh.

The unit added that due to the rainy weather in the area in recent days, construction has encountered many difficulties. The soil and rock in the tunnel area has been weathered for a long time and is becoming softer and more prone to landslides. The railway industry has not yet determined when the repair work will be completed.

At around 10:15 a.m. on May 21, a large amount of rock and soil in the Chi Thanh railway tunnel (Tuy An district, Phu Yen) suddenly fell down while a construction train was reinforcing the tunnel. The estimated volume of rock and soil that collapsed was about 30 cubic meters. After that, the tunnel continued to collapse with a volume of up to hundreds of cubic meters.

Source: https://www.baogiaothong.vn/khoan-ky-thuat-tren-duong-dt641-de-nghien-cuu-bom-be-tong-khac-phuc-sat-lo-ham-chi-thanh-192240522165553141.htm