Ground at Purple Line site 'stable'

Ground movement at the construction site of Bangkok's Purple Line South has stabilised, with unaffected roads expected to reopen within a week as monitoring and repair work continue, the Transport Ministry said 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 Transport Minister Siripong Angkasakulkiat said surveys recorded average ground settlement of 30-32 centimetres, with no further subsidence detected. In areas where contractors injected chemically treated cement grout into underground voids, the ground had 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 on Monday that no abnormalities had been detected for two consecutive days. Underground water flow had decreased to about 20 cubic metres per hour from 50 previously, indicating improving soil stability. He said residents should not return until authorities were satisfied that the area was safe. Subscribe to our newsletters for daily updates, breaking news and exclusive content.