Tanjong Katong sinkhole: Road recovery works progressing steadily, tests under way
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The sinkhole was located near a PUB construction site, which involved sewer laying works.
ST PHOTO: CHONG JUN LIANG
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SINGAPORE – Efforts to prepare a stretch of Tanjong Katong Road South for reopening are progressing steadily, with tests under way to check ground conditions
Mr Herman Ching, director of national water agency PUB’s water reclamation (network) department, told reporters late on July 28 that the sinkhole was refilled early in the day with liquefied stabilised soil, which is made of soil, cement and water.
When poured into the sinkhole, it will fill all the voids in a matter of hours and eventually form a “competent soil-like material”.
“This material will provide the strength needed for road construction later,” said Mr Ching.
Shortly after the sinkhole was filled, work started to test the ground using three methods.
A ground-penetrating radar is being used to check the ground once more and ensure that the sinkhole has been completely filled.
Second, a long metal rod is drilled up to 20m into the ground to test that material and rule out any gaps underground.
Third, a seismic survey, which uses sound waves to scan the area, will allow an evaluation of ground conditions at a greater depth, beyond what the ground-penetrating radar can detect.
The sensors can pick out anomalies that may suggest there are voids underground.
“Collectively, these three methods will give us a good sensing of the competency of the ground in this area, and ensure that the ground is good for road construction, so that we can safely open the road later,” said Mr Ching.
A section of Tanjong Katong Road South caved in on July 26
The stretch of Tanjong Katong Road South between Mountbatten Road and the ECP remains closed to traffic. The sinkhole was located near a PUB construction site with sewer laying works.
The agency added in a statement that it is working towards completing the repairs as quickly as possible, and is conducting thorough safety assessments in consultation with the Building and Construction Authority and Land Transport Authority before reopening the road.
“We seek the public’s continued understanding and patience during this period,” PUB said. “We are working round the clock to expedite the recovery of the road. We apologise for the inconvenience caused to residents and motorists.”
