Singapore’s water agency conducts intensive scans to ensure the site is safe before reopening.
Authorities in Singapore are carrying out rigorous ground tests at Tanjong Katong Road South after filling a sinkhole that swallowed part of the road and a car on July 26, 2025. The incident has prompted a swift but cautious recovery effort.
Emergency Filling with Liquefied Stabilised Soil
On July 28, PUB refilled the sinkhole with liquefied stabilised soil, a mixture of soil, cement, and water that quickly solidifies into a strong, soil-like material. The substance flowed into underground voids within hours, providing a stable base for subsequent repair work.
Advanced Ground Testing in Progress
Following the filling, PUB launched a three-step testing process to confirm ground stability. Engineers are using ground-penetrating radar to scan subsurface layers, metal rod probing up to 20 meters deep to detect hidden gaps, and seismic scanning to identify anomalies at greater depths. These tests will determine if the area is safe for road reconstruction.
Coordinated Safety Assessments
PUB is working closely with the Building and Construction Authority (BCA) and the Land Transport Authority (LTA) to carry out safety assessments before reopening the road. “Collectively, these methods will give us a good understanding of the ground’s competency and ensure safe road construction,” said PUB director Herman Ching.
Incident Linked to Sewer Construction Works
The sinkhole opened near a PUB sewer-laying site after a caisson ring failed during construction. The collapse caused two road lanes to cave in, sending a car plunging into the hole. The driver was rescued by nearby workers and hospitalised for observation.
Residents Report Warning Signs
Some residents reported signs of damage before the incident, including cracked porch tiles and water leakage from a suspected burst pipe on nearby Mountbatten Road. BCA inspections confirmed that adjacent buildings remained structurally safe.
Road Recovery Moving Forward
The affected stretch between Mountbatten Road and the East Coast Parkway remains closed while repairs continue. PUB has pledged to work around the clock to expedite recovery and minimise inconvenience for residents and motorists.
The Tanjong Katong sinkhole has highlighted the need for vigilant monitoring of underground infrastructure during major construction projects. As PUB continues its safety checks, the incident serves as a reminder of the importance of preventive measures to protect Singapore’s urban environment and public safety.
Sources: CNA (2025) , The Straits Times (2025)
Keywords: Tanjong Katong Sinkhole, PUB Ground Tests, Singapore Road Collapse, Sewer Construction Incident, Sinkhole Repair Works
