According to the Hanoi Urban Railway Management Board (MRB), at 4:00 p.m. on February 20, during the digging of the Nhon - Hanoi Railway Station metro tunnel, a phenomenon of tunnel excavation occurred on the ground in the area of lane 7 Giang Van Minh, Kim Ma.
After the inspection, the investor - Hanoi Urban Railway Management Board, along with consultants and contractors, inspected the site. Initially, it was determined that the cause may be that there are still wells underground or old drainage culverts that have created a path for tunnel boring to the ground (these old wells and culverts are no longer in use).
According to the project's schedule, before the tunnel was drilled, the consultant and contractor conducted a survey of the works along the route. However, due to changes in project owners over time, many information are not provided in full, so it is inevitable that there will be a lack of data on underground projects such as water wells, drilled wells of local residents, or geological survey drilling holes from previous projects that have not been filled.
During the drilling process, the tunnel drilling accessories are sprayed with pressure to stabilize the soil in front of the peach mirror. When encountering holes such as water wells and drilling holes, tunnel drilling additives will follow these holes to the ground. This phenomenon only occurred for a short time and ended right after the TBM tunnel excavator drilled through and installed the tunnel lining. This is a common phenomenon during the construction of urban tunnel drilling works.
Immediately after discovering the incident, the investor directed the consultant and contractor to urgently mobilize equipment and human resources to fix it according to the project's process including drilling and cleaning the surface of the damaged area, ensuring safety and environmental hygiene.
Mr. Lee Young Kyeong - Deputy Project Director of Hyundai & Ghella Joint Venture - affirmed: "The phenomenon of tunnel borers melting onto the ground during the boring process was a technical incident that was within the plan and was immediately controlled. We are committed to fully complying with technical standards and safety procedures, and will continue to closely coordinate with investors and related units to ensure the construction process is safe and effective.
The above phenomenon did not affect the structure of the project nor caused any damage to people or property. MRB is closely coordinating with relevant units to accurately assess the cause and deploy technical measures to prevent similar incidents in the next phase.
MRB has been seriously implementing solutions to ensure safety during the construction process, complying with technical standards and current regulations. We will continue to update information on the construction status and coordinate with relevant agencies to ensure the progress and quality of the project".
