On 2/8, contractors began filling the sinkhole on National Highway 3B in Na Ri commune (formerly Kim Lu, Na Ri district, Bac Kan province) with 156 gabions. The project, funded by the state budget at a cost of over 4.3 billion VND, is overseen by the Department of Construction. Its primary goal is to address the serious subsidence that disrupted traffic and impacted residents' lives.

The approved plan involves widening the sinkhole and filling it with steel gabions packed with rocks to stabilize the base. Every three to four layers of gabions will be interspersed with a layer of rocks until reaching approximately 3 meters below the original road surface, where handmade gabions will be used. This will be followed by a 30-cm layer of type-two crushed stone, an 18-cm layer of type-one crushed stone, and finally, three layers of standard 4.5 kg/m2 asphalt. The project is expected to be completed by 31/8.

The sinkhole in Bac Kan province being filled 4 months after it appeared. Photo: Chu Dong

The sinkhole, over 10 meters in diameter and 10 meters deep, first appeared on 29/3 in the median strip of National Highway 3B in what was then Kim Lu commune. Initial attempts to fill it failed as the materials were washed away, forcing authorities to erect barriers and close the road.

Around 9 PM on 27/5, a security camera captured a motorcyclist crashing through the barriers and into the sinkhole. That night, responders recovered pieces of the barrier and what appeared to be the victim's clothing. On the morning of 28/5, a family from Kim Hy commune confirmed that their 36-year-old relative was missing.

Around 50 personnel from the army, militia, and fire and rescue services began searching for the victim on the morning of 28/5. Police in an inflatable boat used grappling hooks, but to no avail.

Seven pumps were used to drain water from the sinkhole. After removing about 5 meters of water, the opening narrowed to about 2 meters. Police rappelled into the sinkhole with grappling hooks but still couldn't find the victim.

On 11/6, Bac Kan province officially called off the search. Authorities stated that despite employing advanced equipment and various methods, the complex terrain and worsening subsidence made recovery impossible and posed a risk to rescue personnel.

Gia Chinh