Jalelah Abu Baker Straits Times 19 Oct 11;
A LANDSLIDE took place on Telok Blangah Hill amid wet weather last month, prompting the National Parks Board (NParks) to close the elevated walkway that winds through the area.
However, some people continue to use the walkway, which wends its way through the secondary forest of Telok Blangah Hill and links to the overhead bridge named the Alexandra Arch.
When The Straits Times visited the trail yesterday, the orange plastic barriers used to block off access to the walkway had been pushed aside.
The walkway, which sits between 3m and 18m above ground, is the Forest Walk portion of the Southern Ridges walking trail, which stretches from Mount Faber to West Coast Park.
The foundations supporting the Forest Walk are sunk into where the landslide occurred, which is near the private houses along Preston Road, off Depot Road.
NParks, which closed the walking trail on Sept 27, has covered the muddy area of the landslide - about the length of a football field - with a large piece of canvas to prevent further soil slips.
Mr Chia Seng Jiang, NParks' general manager, said that because of the landslide, the Forest Walk and the nearby Earth Trail will be closed till further notice for public safety.
He added: 'While works are currently being carried out to stabilise the slope, the public is advised not to venture beyond designated paths.'
Engineering specialists said landslides here normally involve only surface soil, and covering the area with canvas prevents further landslides.
Mr Chong Kee Sen, a civil engineer with more than 20 years' experience, said that because landslides here generally involve shallow surface slippage, they are not likely to affect anyone, unless they are very near to it.
Mr Chong, who is also the vice-president of the Institution of Engineers Singapore, said soil is weakened when it is rain-soaked, and that vegetation can protect it from direct contact with rain.
Professor Harianto Rahardjo of Nanyang Technological University's School of Civil and Environmental Engineering said most rainfall-induced landslides are shallow and involve only 1m to 2m of soil. But the extent of the slide depends on many factors, such as soil strength, and the slope's height and angle.
The professor, who has researched landslides for more than 20 years, said they can be prevented somewhat through regular maintenance and assessment. 'There have been quite a number of small landslides here, particularly after heavy rainfall,' he said.
