How to build on unstable terrains and avoid landslides?

How to avoid landslides?

In today’s blog, we present you examples of good practice in building structures on potentially unstable slopes. The temperatures are falling, the autumn is in front of us and we are expecting soon, wanting or not, the rainy periods that will actualize the subject in geotechnical engineering – LANDSLIDES.

We have already written about landslides, and today we will try to give some advice on how to avoid and reduce landslides. Examples of a good and bad practice of building on unstable terrains are shown in the following chart.

It is good to hire a specialized company for geotechnical research to execute a geotechnical exploration and investigation works and make geotechnical report before starting any construction or new design.

The report encompasses recommendations for landscaping and foundations for future construction. But this is not always a practice. In order to avoid damage due to landslides, we can give you a few guidelines and recommendations.

How to build on unstable terrains?


Figure 1. Recommendations for construction on unstable terrain

1. Try to keep vegetation above the new structure. Although it’s easiest to remove vegetation before the works started to get additional space for works execution, storage, and temporary use. Try to keep vegetation which increases slope stability.

2. Perform the rainfall drainage system above the building and direct it downhill beyond the affected area. The system will serve to drain rainwater and reduce terrain infiltration. If possible, protect the system, to be absorbent as possible and enable water redirection outside the affected area.

3. Make sure the roof drainage is directed outside the affected area, do not discharge it around the building. Check if the system is in function, not blocked or does not discharge water into terrain around the building.

4. If necessary execute the building foundation on rock mass or inside a favorable geotechnical unit. Piles or micropiles are sometimes more expensive, but only at the start. Believe, repairing the damage is much more expensive, and sometimes impossible. Today, there are many types of micropiles, and the cost of this kind of foundation is getting more and more profitable.

5. If necessary, drain the slope with drainage systems and take the water out of the affected area.

6. Avoid the “mass equalization” method, it is not neccessary to install excavated material into the embankment. In some places, you add more weight to the slope and increase the possibility of instability.

7. Septic tanks should be emptied regularly and made properly to avoid leakage. Do not empty the septic tanks in terrain.

8. Retaining structures must be properly designed with an accent on drainage of groundwater and rainwater.

9. Keep the existing vegetation below the construction (downhill).


Photo 1. Tension crack on landslide

Download How to build on unstable terrain and avoid landslides

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