SINGAPORE: It happened in Malaysiahondawin, but the question also arose in Singapore: Are we at risk from sinkholes?
And almost three weeks after a tourist in Kuala Lumpur fell eight metres as the earth opened under her, Singapore’s Building and Construction Authority outlined the measures in place to manage this risk during construction work.
These include builders and engineers monitoring the ground for surface subsidence, it said in a letter to The Straits Times, noting that sinkholes may be caused by tunnelling or excavation work.
Additionally, David Ng, chairman of the Institution of Engineers Singapore’s civil and structural engineering technical committee, told CNA’s Talking Point that construction companies must ensure that retaining walls are built deep enough to block groundwater flow, which could wash soil into the excavation and create voids.
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CNA Explains: What could have caused the Kuala Lumpur sinkhole, and are there warning signs? “During the tunnelling process, we’ll measure the excavated volume of soil (taken) out … so that there’s no void underground, created due to over-excavation,” he said.
If there are voids, ground-penetrating radar — which sends radio waves into the ground — is one method of detecting them, he added.
While such measures have minimised the risk of sinkholes forming, another expert thinks Singapore and the region are likely to see more sinkholes because of climate change.
Climate projections indicate both a hotter and wetter future, “especially in Singapore”hondawin, stated Stephen Chua, a research assistant professor at the Nanyang Technological University’s Earth Observatory of Singapore. “These extremities actually put a greater strain on the sediments underneath.”
Dr Stephen Chua from the Earth Observatory of Singapore, Nanyang Technological University, researches the impact of climate change on Singapore and the region.