A slope is simply an inclined ground separating two different ground levels. A slope can be as high as one meter, several meters, or several hundred meters. The inclination of a slope can be anywhere, from 10 degrees to nearly 90 degrees.
The slope can be natural or manmade.
In most cases so long as the natural slopes and their surroundings are left alone, natural slopes can be said to be stable. However, almost all slopes of concern to us are manmade or in some way altered by man, and therefore do not fall in this category.
In the case of development or construction along hilly grounds, the slopes we are concerned with are manmade. This is because when buildings are built on undulating or hilly grounds, it would be nearly impossible to find a natural flat platform to cater for all structures.
Therefore, the development would have to be situated on different levels. This would involve some cutting into original grounds at higher levels to provide a flat platform and some filling at the lower levels to provide another platform there.
Joining these flat platforms at two different levels will be an inclined ground we call "the slope".
Once completed and the slope project is put into operation, these slopes have to be looked after or maintained to ensure continuous safety against failures.
In 1996, a study was conducted in which a number of schools with slopes were evaluated. At all sites visited, it was found that although the slopes were reasonably well-designed and proper drainage was provided, the maintenance of slopes and drainage was very poor and in some cases, nonexistent.
The effect of the lack of maintenance was found to be so bad that entire slopes required costly redesign and reconstruction. Some of the slopes had already failed, while others were about to fail and could lead to costly damage including loss of life.
Where such extreme cases were found, this meant unnecessary waste of funds and exposure to needless risks to life and limb. Simply stated, these slopes should never have reached the bad state they were in. Most of these could have been avoided by simple maintenance.