At approximately 3 p.m. on May 27, a column of mud roughly 0.5 meters high unexpectedly burst from an underground water meter at house number 25F, C, on Cat Linh Street (Dong Da District, Hanoi), near an active tunneling site of the Nhon - Hanoi Station metro line.

The incident occurred at a section of the underground metro line currently under construction between Cau Giay and Hanoi Station.

By 4 p.m., the mud flow had been contained. Dozens of sandbags were stacked to prevent further overflow. However, the mud had already spread across the sidewalk and into the roadway in front of several adjacent homes, including numbers 25C, F, H, and I.

Local residents alarmed by sudden mud eruption

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Mud flooded the street in front of homes on Cat Linh Street. Photo: N. Huyen

 

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A resident expresses concern over potential water tank contamination. Photo: N. Huyen

 

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Sandbags used to block further mud overflow. Photo: N. Huyen

 

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Environmental cleanup trucks deployed at the scene. Photo: N. Huyen

“I had just been told to evacuate yesterday by the project management team,” said Ms. Lan, the owner of house 25F, C. “So when my neighbor called about the incident, I rushed back and saw mud spurting nearly half a meter high from the water meter located between our homes.”

When Ms. Lan returned, the mud had nearly reached her doorstep. Fortunately, sandbags were deployed quickly enough to block it from entering her home. “My biggest concern now is whether the mud has contaminated the two underground water tanks in the house,” she said.

Shortly after 4:15 p.m., two environmental service trucks arrived to begin pumping out the mud.

Project team activates emergency response

The Hanoi Urban Railway Management Board (MRB) later confirmed the incident, stating it occurred during tunnel boring machine (TBM) operations for the Nhon - Hanoi Station pilot metro project.

The mud eruption took place in front of houses 25C and 25E on Cat Linh Street. MRB explained that the incident happened during excavation with TBM No. 1.

Immediately after detecting the incident, the contractor activated the project's emergency protocol under the supervision of MRB, the project supervision consultant (PIC), local authorities, and other relevant units. TBM operations were halted to reduce the mud outflow while maintaining excavation face stability.

The contractor then mobilized workers, mud suction trucks, and cleanup crews to contain and remove the mud. A reassessment of the local geological conditions is also underway to stabilize the situation and prevent recurrence.

MRB is now working closely with involved parties to determine the exact cause and implement technical solutions to avoid similar incidents in the upcoming construction phases.

N. Huyen