Ground movement at the Bangkok Purple Line South construction site has stabilised after last week’s tunnel water leak, and unaffected roads are expected to reopen within a week, the Ministry of Transport reported on Monday.
Water leaked into a railway tunnel on the Tao Poon–Rat Burana section on July 8, causing ground subsidence and cracks on Prajadhipok Road near Wongwian Yai. The incident prompted road closures, evacuations and inspections of nearby buildings.
Deputy Minister of Transport Siripong Angkasakulkiat said surveys recorded average ground settlement of 30 to 32 centimetres, with no further subsidence detected. In areas where contractors injected chemically treated cement grout into underground voids, the ground has begun to rise slightly.
The Urban Search and Rescue Team (Usar Thailand), working with Kasetsart University, has installed 10 additional monitoring sensors and deployed LiDAR-equipped drones to create three-dimensional maps tracking ground movement. Despite recent rainfall, no further settlement was detected.
Traffic restrictions will remain while contractors seal about 30 underground voids. Unaffected road sections are expected to reopen gradually within a week.
Mr Siripong said repairs were expected to be completed relatively quickly, unlike the prolonged disruption caused by the road collapse outside Vajira Hospital. He added that Prime Minister Anutin Charnvirakul had ordered agencies to expedite assistance to affected residents.
The Mass Rapid Transit Authority of Thailand (MRTA) and contractors are conducting door-to-door visits, covering relocation costs for displaced residents and providing compensation where appropriate.
The Department of Disaster Prevention and Mitigation (DDPM) said inspections found no significant movement in buildings around Wongwian Yai. Although additional cracks were observed in some locations, no structural movement or further road subsidence was detected. Monitoring continues three times a day.
Assoc Prof Amorn Pimanmas, president of the Structural Engineers Association of Thailand, said no abnormalities had been detected for two consecutive days. Underground water flow has decreased to about 20 cubic metres per hour from 50 previously, indicating improving soil stability.
He urged residents not to return until authorities are satisfied the area is safe.
