TPE slip road affected by landslip partially reopens

A Tampines Expressway (TPE) slip road towards Loyang Avenue, that was affected by a landslip triggered by heavy rain over the weekend, has partially reopened.

Repair work has been completed and one lane is now in use while the lane nearer the landslip is being kept closed as a precaution, the Land Transport Authority (LTA) noted in a Facebook post yesterday. The landslip on Saturday caused seven railings by a monsoon drain to give way.

Responding to queries from The Straits Times, a LTA spokesman said it will close off the affected area and mobilise resources to rectify the situation when it detects incidents that may impact the safety of road users, similar to what was done to repair the slope.

It said: " LTA will continue to monitor closely our road conditions and take any necessary precautionary measures to ensure public safety."

Associate Professor Leong Eng Choon from the Nanyang Technological University's School of Civil and Environmental Engineering said the stability of a slope depends on the strength of the soil, which weakens when it becomes wet from the rain.

"Hence, the risk of landslip increases when wet weather persists over a few days. Some landslide risk maps use antecedent rainfall (total rainfall over a few days) as the trigger of landslips."

He added that repairing one spot of the slope does not ensure that another spot will not fail.

He said: "Depending on the type of repair work, the scar where the slip occurred is a weak interface.

"If the repair work consists of compacting soil into the scar to restore the slope's original geometry, the newly added soil may still slide along the scar under wet weather condition."

A video of the slip was circulating on social media.

Motorists heading to Loyang, Pasir Ris or Tampines can take alternative exits at Pasir Ris Drive 12, Pasir Ris Drive 8, Tampines Avenue 12 or Upper Changi Road North, the LTA added. It had said on Sunday that preliminary investigations showed that the stability of the slip road was not affected.

A wet start to the year set off landslips and flood warnings across the island, with areas in Havelock, Fort Canning and Loyang cordoned off as repair work began.

A 22m-high tree on the slope of Fort Canning Hill fell after a heavy storm, damaging a section of the escalators connecting Fort Canning MRT station to the hill's peak.

A muddy mess was also seen at the foot of a slope that connected Outram Secondary School to the Furama RiverFront hotel.

The Singapore Land Authority said in an earlier statement that an engineer assessed that the slope was stable.

It has been covered with canvas sheets before repair work is carried out. The debris at the foot of the slope has also been cleared up.

There were minor landslips on Kusu Island, Lazarus Island and St John's Island on Saturday.

The wet weather is set to persist, with rainfall for the first half of this month expected to be above average over most parts of the island, the Meteorological Service Singapore said.