Road works, not water likely cause, says BMA - Thailand
The Bangkok Metropolitan Administration yesterday found a small hole in a water drainage tunnel under Rama IV Road but could not say whether it caused Sunday's sinkhole.
Officials from the Bangkok Metropolitan Administration use ground penetrating radar (GPR) to check a section of Rama IV Road, starting from Lumpini Tower to the Thai-Belgium Bridge, to try to find the possible cause of a large sinkhole discovered on the road on Sunday.
The hole, which is about 5-8cm in diameter allowed water to flow into the tunnel, Adisak Khantee, deputy director of the BMA's Department of Drainage and Sewerage said after using a robot equipped with a CCTV camera to inspect the four-decade-old tunnel. The hole was in the upper part of the tunnel and water flowing into it was fairly clean with no soil or sand mixed with it, said Mr Adisak.
It was unusual for a hole to appear in the upper part a drainage tunnel, he noted.
The BMA suspects the hole could have been caused accidentally during road works.
Normally, other agencies wanting to lay pipelines or carry out work involving the drainage tunnel would have to seek permission from City Hall first, he said.
Department chief Sanya Cheenimit said he could not determine whether the hole was the cause of the sinkhole which appeared on Sunday. He added that he would report the leak to BMA executives.
The BMA will meet agencies responsible for public utility services next week to try and establish the cause of the sinkhole.
Authorities earlier assumed Sunday's subsidence which happened around 7pm on Rama IV Road near the Witthayu intersection resulted from a leak in the drainage tunnel.
Deputy Bangkok Governor Wallop Suwandee said he has already met with Deputy Bangkok Governor Teerachon Manomaiphiboon, who supervises the BMA's public works, about the cause of the sinkhole and that they had agreed the Engineering Institute of Thailand would be invited to jointly inspect it.
He said water entering the drainage tunnel might have washed away sand beneath the road. However, experts would determine the exact cause of the sinkhole, he said.
On Tuesday, the BMA checked a wastewater drainage system under the Thai-Belgium Bridge to try to find the possible cause, however it came up with nothing amiss.
Mr Teerachon yesterday said the entire length of Rama IV Road, except where the sinkhole occurred, has been laid with reinforced concrete.
He has ordered the Public Works Department and the Pathumwan district office to check on contractors who have been hired recently to carry out work near the sinkhole's location. The two agencies would then check whether any repair work was up to standard or not.
If the work is found to be substandard, the firm would be put on a BMA blacklist and would not be given any future work by City Hall, the deputy governor said. He has also asked all 50 district offices to check their roads.
Thanes Weerasiri, secretary-general of the Engineering Institute of Thailand, said the institute was willing to inspect the sinkhole if asked by the BMA. Ultrasound would be used to examine the road and underneath it, he added.
The Bangkok Metropolitan Administration yesterday found a small hole in a water drainage tunnel under Rama IV Road but could not say whether it caused Sunday's sinkhole.
Officials from the Bangkok Metropolitan Administration use ground penetrating radar (GPR) to check a section of Rama IV Road, starting from Lumpini Tower to the Thai-Belgium Bridge, to try to find the possible cause of a large sinkhole discovered on the road on Sunday.
The hole, which is about 5-8cm in diameter allowed water to flow into the tunnel, Adisak Khantee, deputy director of the BMA's Department of Drainage and Sewerage said after using a robot equipped with a CCTV camera to inspect the four-decade-old tunnel. The hole was in the upper part of the tunnel and water flowing into it was fairly clean with no soil or sand mixed with it, said Mr Adisak.
It was unusual for a hole to appear in the upper part a drainage tunnel, he noted.
The BMA suspects the hole could have been caused accidentally during road works.
Normally, other agencies wanting to lay pipelines or carry out work involving the drainage tunnel would have to seek permission from City Hall first, he said.
Department chief Sanya Cheenimit said he could not determine whether the hole was the cause of the sinkhole which appeared on Sunday. He added that he would report the leak to BMA executives.
The BMA will meet agencies responsible for public utility services next week to try and establish the cause of the sinkhole.
Authorities earlier assumed Sunday's subsidence which happened around 7pm on Rama IV Road near the Witthayu intersection resulted from a leak in the drainage tunnel.
Deputy Bangkok Governor Wallop Suwandee said he has already met with Deputy Bangkok Governor Teerachon Manomaiphiboon, who supervises the BMA's public works, about the cause of the sinkhole and that they had agreed the Engineering Institute of Thailand would be invited to jointly inspect it.
He said water entering the drainage tunnel might have washed away sand beneath the road. However, experts would determine the exact cause of the sinkhole, he said.
On Tuesday, the BMA checked a wastewater drainage system under the Thai-Belgium Bridge to try to find the possible cause, however it came up with nothing amiss.
Mr Teerachon yesterday said the entire length of Rama IV Road, except where the sinkhole occurred, has been laid with reinforced concrete.
He has ordered the Public Works Department and the Pathumwan district office to check on contractors who have been hired recently to carry out work near the sinkhole's location. The two agencies would then check whether any repair work was up to standard or not.
If the work is found to be substandard, the firm would be put on a BMA blacklist and would not be given any future work by City Hall, the deputy governor said. He has also asked all 50 district offices to check their roads.
Thanes Weerasiri, secretary-general of the Engineering Institute of Thailand, said the institute was willing to inspect the sinkhole if asked by the BMA. Ultrasound would be used to examine the road and underneath it, he added.
