Speeding up each drill bit to clear the Deo Ca railway tunnel

Establishing a forward command team, increasing human resources, specialized equipment, concentrating on day and night construction... are a series of solutions being deployed by the Ministry of Transport, investors and construction units to overcome landslides at Ca Pass as soon as possible, trying to open the railway tunnel on April 22.

"Hit below, drill above"

Late afternoon, having just had a lunch box, Mr. Nguyen Van Quang, Commander of Song Da 10 Joint Stock Company, quickly wiped his sweat and entered the southern entrance of Bai Gio tunnel (North-South railway tunnel through Ca Pass, Dai Lanh commune, Van Ninh district, Khanh Hoa province). His task was to directly follow the construction tip to drill anchors, spray, and erect steel frames.

Deputy Minister of Transport Nguyen Danh Huy gave instructions at an online meeting with the field working group, agencies, units, and the two provinces of Phu Yen and Khanh Hoa on the morning of April 16 to discuss a plan to overcome the collapse of the Bai Gio railway tunnel. Photo: Ta Hai.

Amidst the rumbling sound of the machine and the dust, tunnel boring machine operator Nguyen Van Cuong (52 years old, Song Da 10 Joint Stock Company) operated the specialized equipment while signaling with his hands to the command units. "The dust was so bad that it was difficult to see and hear each other clearly. We could not open the ventilation holes like other tunnels to shorten the construction time," said Mr. Quang.

Under the yellow electric lights, the air in the tunnel was hot, occasionally the piercing sound of drills hitting the hard rock layer echoed, but it did not make the engineers and workers falter. Skillfully controlling the specialized 3-bit drill like a trident stuck into the rock wall, Mr. Cuong coordinated smoothly with the adjustment department, signaling to adjust the drill bits to the appropriate positions.

For many days now, more than 100 officers, engineers, workers and specialized equipment of Song Da 10 Joint Stock Company have been reinforced from the Son Trieu tunnel construction site (XL11 package, Quy Nhon - Chi Thanh expressway) to strengthen the work of overcoming the landslide of Bai Gio tunnel. Every day at the construction site, the three construction sites are fully concentrated by the contractors, like a battle formation "attacking from below and drilling from above".

Construction through the night

According to the reporter, there were hundreds of workers and engineers rushing to drill anchors, erect frames to increase the tunnel shell structure and drill bits from the top down to the collapsed position with a distance of more than 23m to pump reinforced concrete.

Previously, at the meeting to discuss the plan to overcome the collapse of the Bai Gio railway tunnel, Deputy Minister of Transport Nguyen Danh Huy directed the establishment of a forward command team led by the leader of Project Management Board 85, and a working group of the Ministry of Transport led by the Deputy Minister of Transport. Deputy Minister Nguyen Danh Huy requested the implementation of the "4 on-site" principle according to emergency situations. At the same time, ensure 5 requirements: earliest route opening; fastest mobilization of forces; most creative solutions; absolute safety for officers, engineers, and workers participating in the recovery; units focus the highest resources on construction 24/24 hours in accordance with the direction of the Prime Minister.

Late afternoon, in the area north of the tunnel, construction was still going on urgently. About 100m from the tunnel entrance, a landslide of rock and soil caused the tunnel to be sealed. Dozens of workers from the Construction Investment and Construction Joint Stock Company 3 were installing the support frame. The hot air made many people suffocate. Outside, an excavator was deployed to level the ground to install the A-shaped steel frame ready to support the tunnel shell.

Mr. Nguyen Thanh Hoai, Director of Project Management Board 85, Head of the Forward Command Team, said that in recent days, the unit has dispatched professional construction forces and a series of new solutions to replace the initial calculations.

Accordingly, specialized equipment and combat forces of Song Da 10 were dispatched to the construction site, set up construction teams and sprayed concrete to harden the landslide locations both above and below. "This new solution has the advantage of completely treating landslide locations and high-risk landslide locations," said Mr. Hoai.

In recent days, the construction site has been almost sleepless, working through the night, while regularly holding meetings to discuss and check progress. Up to now, after the reoccurrence of landslides, functional units of the Ministry of Transport, the railway industry, Project Management Board 85, design consultants, and supervision consultants have strengthened a series of new solutions, which are bringing positive results.

Efforts to clear the route as soon as possible

At noon on April 18, the forward command team met right at the construction site. According to the report, the teams mobilized 8 specialized equipment, sprayed nearly 30m3 of concrete, manufactured 60 cell anchors, and completed 36 sets of type A support frames...

Construction teams of Song Da 10 contractor were mobilized to speed up the handling of the landslide incident at Bai Gio railway tunnel. Photo: Cao Son.

Although the anchor drilling work has reached 37 holes, 29 anchors have been installed to create cells, but according to the contractor, this work is facing difficulties due to the geological collapse behind the tunnel lining, causing the drill pipe to get stuck during the implementation process. Therefore, the contractor is required to strengthen the solution, change the location of the drill hole many times to avoid getting stuck, affecting the progress.

According to Mr. Nguyen Thanh Hoai, following the direction of the Ministry of Transport, the forward command team was established at the construction site, meeting to count the progress daily and hourly and reporting to the Ministry of Transport Working Group twice a day to promptly remove and handle arising issues. Up to now, the basic technical critical lines have been handled, the progress is under control, striving to open the tunnel on April 22.

Bai Gio Tunnel is 393.72m long, is a level II railway tunnel project, is being solidified, the capital source is from the medium-term public investment plan for the period 2016 - 2020, with Project Management Board 85 as the investor.

At about 12:45 on April 12, during the blockade to carry out construction at Km 1231+089.48 - Km 1231+090.73, a weak geological layer collapsed on the tunnel dome, the volume of rock and soil falling down was about 150m3, disrupting railway train operations; there was no damage to people or construction equipment.

Immediately after the incident, the Ministry of Transport reported to the Prime Minister and directed the forces to urgently fix the problem. The Prime Minister issued telegram No. 37, in which he assigned the Ministry of Transport to urgently direct the mobilization of all resources to clear the route as soon as possible.

In addition to overcoming and handling landslides to clear the tunnel, the transport sector has transferred railway passengers by road through the Hao Son - Dai Lanh section and regulated the flow of cars through Ca Pass.

According to Nha Trang Railway Transport Branch, as of April 18, the unit has supported the transfer of nearly 21,000 passengers on 73 trains via road to continue their journey.

Source: https://www.baogiaothong.vn/tang-toc-tung-mui-khoan-thong-ham-duong-sat-deo-ca-192240418233903581.htm