Bangkok Governor reports continued land subsidence at Samsen Police Station, sets plans for prevention

Bangkok Governor Chadchart Sittipunt on Wednesday provided an update on the ongoing situation involving land subsidence along Samsen Road, near Vajira Hospital, which has led to a large sinkhole. He reported that, in the afternoon, further landslides occurred in the deep hole, likely caused by water flowing into the area. Additionally, a shaft hole (drainpipe opening) allowed soil to move into the tunnel and the MRT station below.

To address the issue, the Mass Rapid Transit Authority of Thailand (MRTA), along with the contractor, has deployed over 50,000 sandbags to seal off the water flowing into the tunnel, which could cause further subsidence. This measure has stabilised the situation, although shaft hole points still require further collaboration with the contractor and MRTA to ensure the sandbags are positioned effectively.

The Governor explained that additional concrete pouring will be done in areas with sandbags to further stabilise the ground and stop further soil movement. As for safety concerns, the Samsen Police Station building is at risk because the soil beneath it is flowing away, which threatens the building's stability. Sukhothai Road also showed signs of movement, and the BMA has already prohibited heavy vehicles from entering the area. Experts will continue to assess whether further traffic restrictions on Sukhothai Road are necessary.

Regarding the safety of nearby hospital buildings, the two buildings are not expected to be affected, said Chadchart, adding that the Waterworks Department has already stopped water drainage, and the Water Drainage Office has used sandbags to block water flow, reducing water levels in the area. Plans are also in place to prevent rainwater from entering the collapsed area in the future, with sandbags set up as a water barrier.

The Governor also confirmed that many residents have already moved to temporary shelters, with some staying in hotels. As for the shophouses near Samsen Road, 21 tenants have been accounted for, and the authorities have successfully managed the situation.

Chadchart said that the focus now is to assess the number of households affected by the lack of water supply or electricity in Samsen’s nearby communities. The Bangkok Metropolitan Administration (BMA) will conduct detailed inspections to see what additional assistance can be provided. “The main priority right now is to stop water from flowing into the tunnel,” he added.

Regarding the ongoing land subsidence, Chadchart mentioned that the situation has slowed down significantly. The use of a laser measuring device, which is the same one used by the State Audit Office (SAO), has been implemented at two points to monitor movement. The soil subsidence started in the Samsen Police Station area, and if it continues, it could cause damage to the station’s structure.

He further explained that the team has started sealing gaps with sandbags to prevent water from entering the tunnel and further soil movement. “We need to block the opening, as if it’s a door,” he stated, adding that this method is the best solution. “We can dig it out later if needed, without damaging the building,” he explained.

Regarding the quantity of soil and water, Chadchart said that they estimate around 7,000 cubic metres in total for the affected area, measuring 30 x 30 x 20 metres. He explained that, although the soil movement has slowed down significantly, there is still a risk, and heavy rainfall could further affect the stability, potentially changing the slope.

“The main cause of the soil movement is when the ground has nowhere to go; once blocked, the movement will stop. However, heavy rain can change the slope and affect the stability,” Chadchart said. He clarified that the tunnel structure remains intact and the movement of the earth had no direct impact on the tunnel’s integrity.

The construction is a joint venture of Sino-Thai Engineering & Construction Public Company Limited, with CH. Karnchang being the contractor, and the drilling equipment coming from abroad. This issue has never occurred before, and the MRTA will provide an initial explanation at 11:00 am tomorrow, said Chadchart.

Meanwhile, Vajira Hospital's representative stated that no patients have requested to be transferred. The hospital confirms that all buildings are safe, as they have deep earth barriers that cover the area of damage. All buildings have been inspected and are confirmed to be in normal condition. Additionally, patients who need medication have been scheduled to ensure they do not run out of supplies. However, there may be slight traffic congestion, and staff have arranged for a U-turn route to access Sangkhalok Road for service.

Furthermore, authorities have advised the public to avoid the area or use public transport, as Sangkhalok Road is very narrow and traffic congestion is expected this Friday.