‘Sinkholes more likely to appear during rainy season’

PETALING JAYA: A geotechnical engineering expert said sinkholes more commonly appear in roads in the country during the rainy season.

Prof Dr Fauziah Ahmad of Universiti Sains Malaysia said rainwater could lead to soil movement that causes sinkholes to form.

“Rain is a triggering factor as the water flow can be very strong and dynamic,” she said, adding that it is important to be extra cautious during the monsoon period.

Sinkholes, she said, appear when there is a cavity below the ground that causes the soil to suddenly give way.

“When there are strong vibrations or movement on top and there is a cavity below the ground, the sand or soil could erode little by little, and then it will abruptly collapse,” she added.

Prof Fauziah said sinkholes could happen because compaction of the road was not done properly.

“Also, former mining land is especially susceptible to sinkholes,” she added.

She said sinkholes regularly occur in other countries as well, giving an example of how a massive sinkhole, spanning five lanes on the road, appeared in Fukuoka, Japan in 2016.

Construction companies, she added, must be thorough and diligent in carrying out the site inspection before building roads.

“Only then will they know and understand what the soil condition is like beneath the planned development site.

“Once they know that the land was previously used for mining and where the cavities beneath the surface are, then proper precautionary measures can be taken,” she said.

She said this was especially important as soil conditions might even differ every 100m.

A Public Works Department spokesperson said the sinkholes could be caused by water not flowing through the correct channels.

Among the other factors include soil movement, broken utility lines under the road surface or unstable pavement foundations.

The spokesperson said that for new roads, the department has determined that locations to install utility lines must be out of the rightof-way.