Massive Sinkhole Swallows Road Near Vajira Hospital in Bangkok
How a Subway Tunnel Triggered a Massive Sinkhole
Early on September 24, 2025, commuters on Bangkok’s Samsen Road witnessed the pavement melt away like quick‑sand. The cavity, now estimated at about 900 square metres and as deep as 50 metres, appeared directly in front of Vajira Hospital in the Dusit district. Video footage shows the ground sagging, pulling down two electricity poles and cracking water mains as drivers scrambled to reverse their vehicles.
City officials traced the origin to an underground train station under construction. When a segment of the tunnel wall collapsed, the overlying soil lost its support and slid down into the void. A ruptured water pipe flooded the nascent hole, accelerating the erosion. Director of the disaster‑prevention department, Suriyachai Rawiwan, linked the event to recent heavy monsoon rains that had saturated the subsoil, making it more susceptible to failure.
Three cars were left dangling over the abyss, their wheels dangling on the edge, while nearby traffic lights flickered out as power was cut. The four‑lane thoroughfare was split in two, with one side terminating abruptly at the edge of the gap, right next to a local police station whose foundation was now exposed.
Official Response, Safety Measures, and Wider Impact
Bangkok Governor Chadchart Sittipunt confirmed that, miraculously, nobody was hurt. He ordered the police precinct to be declared a danger zone and oversaw the evacuation of officers and residents within a 200‑metre radius. Vajira Hospital shut its outpatient department for two days as a precaution, though in‑patient services continued because the hospital’s underground reinforced walls remained intact.
Prime Minister Anutin Charnvirakul visited the site, noting that the slide of construction debris into the sinkhole was the primary cause and praising the quick actions of emergency crews. Teams from the city’s disaster agency, water authority, and electricity provider arrived within minutes to assess damage, shut off utilities, and begin stabilising the ground.
Engineers plan to backfill the void with a mix of cement‑based grout and rock ballast, a process expected to take several weeks given the depth and the ongoing monsoon rains. Meanwhile, detour routes have been set up, diverting thousands of vehicles onto parallel streets and causing gridlock during peak hours.
The incident has reignited public concerns about Bangkok’s rapid subway expansion. Over the past decade, the city has launched three major mass‑transit lines, adding dozens of kilometres of underground tunnels beneath an already flood‑prone metropolis. Critics argue that inadequate geotechnical surveys and rushed construction schedules increase the risk of similar failures.
Local businesses along Samsen Road report a sharp dip in foot traffic, and residents fear prolonged disruption to water and electricity supplies. Authorities assure that repairs to the damaged water pipes and power lines will be completed before the monsoon season peaks, but they warn that continued heavy rain could destabilise the freshly backfilled area.
As Bangkok grapples with the aftermath, the sinkhole stands as a stark reminder of the delicate balance between urban growth and geological reality. The city’s engineers, policymakers, and citizens alike will be watching closely to see whether the measures put in place now can prevent a repeat of what many are calling the most dramatic infrastructure failure in recent Thai history.