In areas prone to landslides, during high rainfall, coupled with unstable slope conditions, greatly span against sliding. The rainwater that seeps into the soil, besides lowering the value of soil cohesion, also increases the mass of the soil. Of the several landslide cases that occurred during this time, there are six main types of avalanches, including: flow, collapse, sag, sliding, creeping and falling. All types of landslides are caused by the absence of a strong bond between the topsoil and the bedrock layer underneath.
In stable slope conditions the topsoil mass is able to withstand the cohesion between topsoil soil particles, adhesion of the topsoil and bedrock layers. If there is vegetation in the topsoil, the existing vegetation roots are also able to withstand gravitational forces by the soil mass due to slope or slope.
Meanwhile, on the slopes caused by human activity, stability can be obtained by building plaster, lining, retaining wall, and so on. But unconsciously people often make mistakes by changing the conditions of the origin of the slopes, by increasing the mass on the topsoil layer, such as erecting buildings and changing the original vegetation. Or in other words, changing the function of land without doing treatment that can anticipate changes in slope conditions, so it becomes unstable.
Soil types also have a major effect, since each soil type has a different slip angle. This slip angle determines the magnitude of the maximum angle capable of being made by a stable soil type. In addition, land use factors also have roles associated with slope stability. The faster the rate of land use change and forest clearing, the greater the risk of landslides.
Landslide prevention efforts have been largely done from traditional or simple methods and evolved to complex and expensive technological methods. For avalanche prevention methods the right way is by building retaining wall or sheet pile on the slope that you can see at https://www.maccaferri.com/my/solutions/mass-gravity-retaining-walls/. They are able to counter the forces arising from morphological changes in the slopes, most of which are either steeper or higher. However, the use of this method has not been able to anticipate the existence of small avalanche, because the ways above have not been able to tie each item well. The only protected edge of the slope is given a retaining wall, while the topsoil is left open.
The selection of appropriate methods to be applied to different land conditions is an important point for stakeholders to create optimal conditions, without neglecting the main function of retaining land.