HCM CITY — Just a day after the first dangerous sinkhole, big enough to “swallow” a bus, was found on Trường Sa Street in the city’s Phú Nhuận District, another deep hole appeared 50 metres away from the original location.

So far, no injuries have been reported. But the serious land depression on the street along Nhiêu Lộc – Thị Nghè Canal, which also happened in 2012, sparked concern over the road construction quality from the public.        

The incident, which occurred over 49 square metres on Thursday, was located in the area of the city’s Environmental Sanitation Project. The holes appear to be getting bigger.

Authorities and experts have been tracing the causes of the land depressions.

An initial investigation showed that a connecting joint between 7-meter underground water drainage sewers was broken, causing water to overflow from the sewer and undermine the underground soil structure, leading to the creation of the sinkhole.

During a meeting on Friday, Lê Hoàng Minh, deputy director of HCM City Department of Transport, said a solution will be carried out to prevent further land depressions.

The authority closed the drainage system to prevent further depressions and determined the location for repairs.

Hà Ngọc Trường, deputy chairman of HCM City Bridge, Road and Port Association, told local press that the location of the dangerous hole is near an area of the construction project No.7A and No. 10 under the HCM City Environmental Sanitation Project, the first phase done by Chinese contractors.

Several holes appeared in the city a few years ago. Trường said the holes that appeared recently are the biggest ones ever in the city.

Concerned agencies had to use barriers to block the area from traffic for safety reasons. Fences erected around the holes caused heavy traffic congestion near the area.

The engineer warned that it’s possible for the holes to become much bigger, threatening houses nearby.

Answering a question about whether the incident has a connection with the Chinese contractors, Trường said that there has been no evidence for coming to that conclusion.

“It is too early to say that the holes were left behind by the careless performance of Chinese contractors on the project. We need to make a geological survey to determine the broken point. If the study finds that the incident is caused by the careless performance of the contractors, I will make a condemnation and propose a penalty,” Trường said.

Nguyễn Vĩnh Ninh, an official at HCM City’s Department of Transport, confirmed that the holes were in the area of construction package No. 10.

The construction was covered by the China State Construction Engineering Corporation, which carried out the project very slowly, sparking concerns from the local government.

Dr. Phạm Sanh, an expert in bridge and road construction, denied the theory that weak geological conditions caused the sinkholes. With weak soil condition, the holes would not happen partially.

 “So the holes were caused by a mistake in design or careless performance during construction. The site should be examined to determine the cause,” Sanh said. — VNS