October 7, 2022

Maintenance key for slope safety

3 min read

IT has been reported that Malaysia needs to monitor some 40,000 landslide prone spots along our roads, highways, and townships.

We already know that the country, by and large, receives a rather high amount of rainfall every year.

With climate change, however, we may get more violent storms that unleash a lot of rainfall within a short time, causing flash floods and triggering landslides.

It is worth remembering that slope failures are not confined to engineered slopes, or places where man has left his imprint.

Landslides happen in nature all the time, whether on disturbed or undisturbed locations, contrary to popular opinion that development must always be to blame.

When it comes to engineered slopes, three elements must come together to ensure long-term stability and safety to the public.

First, the slope must be well designed. This must be followed by good construction quality. Finally, there must be good maintenance post-construction.

Even the gentlest of slopes can fail, and inversely, it is not necessarily true that a steep slope is destined to fail.

It is all in the engineering, construction and maintenance.

We are fortunate that in terms of engineering and construction, Malaysian engineers can stand head-to-head with the world’s best.

Take, for example, our band of seasoned slope engineers involved in the construction of some of the most difficult to build roads ever, such as the 60km KL-Karak Expressway, and the 112km East-West Highway from Gerik in Perak to Jeli in Kelantan.

Following this, we also built many more roads through mountainous terrain, thus increasing our competency in slope engineering and construction.

The government knows that the ideal way to construct roads through mountains is to opt for tunnels and viaducts instead of cut-and-fill methods, even though the latter is several times cheaper.

With tunnels and viaducts, there is very little cutting of hills and this is the best way to design a road across mountainous terrain.

For example, in Japan, roughly 90% of their highways are built across tunnels and viaducts, though admittedly, these do not come cheap.

For those who are critical of the many landslides in the past, perhaps a previous shortcoming decades ago was that there was no real marriage between the engineering geologists and the geo-technical engineers.

The former tend to focus on rocks while the latter, on soils. But roads are built on both rock and soil.

Perhaps we didn’t even have enough of both groups in the early days.

But now, both disciplines work side-by-side to ensure project success.

Therefore, we can rest well, knowing that we have the best slope designers and builders.

Right now, Malaysia has several of the most competent slope engineering specialists.

Of course, maintenance is the final frontier where we have to prove our commitment.

It is heartening to know that the Works Ministry will be carrying out landslide prevention work on slopes along 236 federal and 129 state roads for this year, backed by an allocation of some RM300mil.

For slopes along federal reserve and state roads, monitoring is being carried out by the district PWD officers via site visits.

However, concerned citizens are not wrong to ask whether our municipal councils are equipped with the right expertise to look after roads under their jurisdiction.

In this, municipalities should demonstrate their commitment to good maintenance, which does not yet seem a normal feature here, judging by the other potential hazards on the road.

Whether or not high-tech slope sensors are available, the public can play its part by reporting potential slope failures or other hazards, both on and off the road.

A good maintenance culture can, or should, go hand-in-hand with the provision of easy-to-use channels for public feedback.