Sinkholes — is depression or destruction of the earth's surface, such as limestone cracks and expanding faults. They are also formed when acidic water percolates through the soil and leads to destruction for a long period of time.
So, there are two main types of sinks:
- Rill (Polje) formed when limestone is exposed or is covered with a thin layer of soil. Once the limestone lining has eroded the soil begins to sink, gradually forming a cup-like depression, which often turns into a swamp or pond.
- Dips (mines, Ponor) formed instantly. When underground cavern can no longer maintain the upper layer, it collapses and opens failure. It happens without warning and may result in loss of life and property.
While these types of events often occur after a heavy accumulation of precipitation in a short period of time, they can occur in extremely dry conditions, when the ground water beneath the surface are mere drops or completely dry.
There are few visible signs that can lead to failure:
- Fresh impact on the poles, foundations and trees, resulting deflection earth's surface
- Warping, sagging or bending of poles, trees and other objects
- Doors and windows that do not close before the end of
- Flooding: A small lake in the places where the water was not going before
- Wilting of small round areas of vegetation because the moisture generally support the plants in these places, dry under the surface in the place of the dips
- Turbidity of the water in nearby wells
- Structural cracks in walls, floors and sidewalks
- Cracks on the surface of the earth.
Cases of failure
Schemes of caverns and education failures of soil: