The reopening of Samsen Road has been postponed indefinitely after authorities concluded that the police station next to the sinkhole that formed on Sept 24 must be demolished and rebuilt, Bangkok Governor Chadchart Sittipunt said on Saturday.
He made the comment following a meeting with a technical task force at the site to reassess the situation. Members included representatives from the police, Mass Rapid Transit Authority (MRTA), Department of Public Works and Town and Country Planning, Bangkok Metropolitan Administration (BMA) and the construction contractor.
Over the past week, about 3,000 cubic metres of sand have been poured, and additional foundation piles installed. However, more cracks and soil slippage were detected, particularly around the third structural pillar of the Samsen police station, which has sustained further damage, said Mr Chadchart.
Technical experts warned that failure to proceed with demolition could pose risks of collapse during restoration work.
The MRTA and the contractor will bear the full cost of the demolition, estimated at over 40 million baht, the governor said.
He outlined six immediate directives:
Remove about 30 vehicles from the station and begin dismantling the rear wall.
Start demolition with the most at-risk right wing to reduce structural load.
Reinforce the Samsen side adjacent to the Vajira intersection to prevent further soil slippage.
Strengthen the underground rail tunnel below the site.
Monitor the structural integrity of the nearby police flats.
Monitor the stability of Vajira Hospital’s buildings.
The governor said work could begin immediately. While no completion date has been set, authorities stressed that safety would remain the top priority.
The planned reopening of Samsen Road has been delayed indefinitely, though traffic impact is currently limited due to school closures. (Story continues below)
Further weakening
The decision to demolish came after subsidence from the initial sinkhole damaged the fifth foundation column of the police station – a key load-bearing support – with soil displacement further weakening the third column.
Attempts to reinforce the foundation failed, as piles could only be driven 7-8 metres instead of the planned 23 metres. The building continues to sink and tilt, with more cracks and soil slides appearing.
Officials stressed that the damage was not caused by machinery filling sand beneath the station but by ground instability.
The demolition will proceed in stages, with debris transported off-site. No materials will be stored on the premises to ensure safety.
Vajira Hospital has shown no movement since the incident took place. Nevertheless, the BMA said monitoring of adjacent structures and underground tunnels would continue.
Despite heavy rain, officials said the operation has not been hindered, as sufficient water pumps have been installed to handle flooding.
MRTA deputy governor Kittikon Tanpao said the exact cause of the subsidence has yet to be determined, as the focus has been on restoring road conditions and securing nearby buildings to prevent further damage.
PM visits site
Prime Minister Anutin Charnvirakul, who visited the site on Friday night, said the severe structural damage to the police station posed a safety risk.
‘The piles are broken. Just by looking at it, I saw that it’s dangerous. Samsen police will need a new workplace,’ he said on Saturday morning. ‘The structure has begun to detach from its core. We cannot allow anyone to continue working inside.’
National police chief Kittharath Punpetch said there is currently no indication that the police flats need to be torn down or rebuilt. ‘At this stage, the urgent priority is the Samsen police station building,’ he said.
The BMA had earlier set Oct 9 as the reopening date for Samsen Road but that plan has now been abandoned.
The sinkhole was 30 metres wide, 30 metres long and 20 metres deep when it formed suddenly on the morning of Sept 24. The MRTA initially blamed it on soil sliding into a tunnel and underground station of its Purple Line extension route.
The contractor for the section in question is the CKST joint venture, made up of SET-listed Ch. Karnchang Plc and Stecon Group Plc. The family of Prime Minister Anutin is the largest shareholder in the latter.