Deputy Minister Le Dinh Tho inspected directly with his naked eye and electronic microscopy magnification of cracks in Hai Van tunnel 1. Photo by Quang Toan /BNEWS / Vietnam News Agency
In recent time, the media has informed about the Hai Van 1 tunnel appeared many cracks which was scattered in the south of the tunnel. To have a comprehensive assessment of this issue, on the afternoon of October 25th, Ministry of Transport task force led by the Deputy Minister Le Dinh Tho directly inspected the site and directed investors to deploy safety methods and track the cracks.
At the scene, after listening to the specialized agency reports and directly inspected with the naked eye and electronic microscopes magnification of cracks in the Hai Van 1 tunnel, Deputy Minister Le Dinh Tho confirmed that “the cracks at Hai Van 1 tunnel through checking and evaluating that in the permitted conditions of exploitation, without affecting the process of construction of the second tunnel -pipe of the Hai Van tunnel project”.
“The Ministry of Transport will establish a working group consisting a few experienced experts and specialized units of the Ministry of Transport to combine regularly with investors to monitor and take measures to deal with cracks which has development signs.” The Deputy Minister Tho said.
In order to ensure the process of tracking cracks conveniently and objectively, Deputy Minister Le Dinh Tho has directed investors, contractors and operation units of Hai Van 1 tunnel to keep the cracks intact like now, do not repaint or sanitize.
According to Assoc. Prof. Dr. Hoang Ha (Head of Science and Technology Department - Ministry of Transport) the cracks of Hai Van 1 tunnel had existed before the delivery this tunnel to Deo Ca Joint Stock Company since January, 2016.
The total number of cracks recorded was 321; 8 of them in the unfavorable status have been repaired by the Ministry of Transport. The rest of cracks are monitored and checked frequently.
According to Assoc. Prof. Dr. Hoang Ha, the current cracks didn’t expand compared to the time of January 2016. This is shown through the parameters of the wideness and the crack’s length doesn’t change. A crack was attached to small plasterboard, if the plasterboard is broken, this means the cracks are developed; however, the plasterboard does not crack or break currently.
“The Ministry of Transport will establish a working group consisting a few experienced experts to combine with investors to monitor and take methods to deal with the cracks.”
Photo by Quang Toan/BNEWS/Vietnam News Agency.
Explaining the images of widespread cracks recorded by the press, Assoc. Prof. Dr. Hoang Ha said that “The tunnel shell has been covered with epoxy paint since 2005. This paint layer are getting old after 13 years of use (The expiry date of this paint according to the technical standard is around 5-7 years), especially in cracks.
In addition, due to sanitizing, washing the tunnel shell with water made the paint peeling widely expand. “Cracks don’t develop but peeling paint makes sensory cracks to develop, leading to concerns about the tunnel safety. However, we confirm that the crack is under close control, there is no development phenomenon and without risk of unsafe”, Mr. Ha emphasized.
Assoc. Prof. Dr. Hoang Ha also said that the cracks only exist in the tunnel cover and it has no bearing effect (the bearing part is anchored structure and sprayed concrete inside).
Regarding the impact of blasting in the construction of Hai Van 2 tunnel, the leader of the Department of Science and Technology said that he had worked with the supervisors of the Vietnam Blasting Association and the site inspector of the Federal Republic of Germany and confirmed construction measures to ensure safety for Hai Van 1 tunnel.
Conclusion at the cracks inspection at tunnel pipe 1 and the construction progress of the second one of Hai Van tunnel. Deputy Minister Le Dinh Tho assessed that the investor has strictly followed the crack monitoring and management process required by the Ministry of Transport before start construction and currently they fulfilling this requirement.
Besides that, the Deputy Minister commended the investor (Deo Ca Investment Joint Stock Company), the construction contractor (Sai Gon Bridge Road Construction Investment Joint Stock Company), the site inspector organized professional and scientific construction.
Until now, nearly 1,300 meter of tunnels have been constructed (more than 20% of the total length of the tunnel); proposed to strive to put the project into operation and exploitation by the end of 2020, 6 months before established progress.
Quang Toan
