Suffosion

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Suffosion (solution erosion, surface solution) is the relocation and removal of fine soil particles in the soil by water. In this process, fine grains of non-uniform, non-cohesive soil are loosened from the soil by the flow force of the water and transported through the existing pore space. The relocation can lead to a reduction in the permeability of the soil structure ( colmation ) elsewhere and impair drainage measures. In addition to suffosion, the displacement of material caused by water through erosion is also significant .

When the fine soil particles are transported away through the pores of the coarser soil particles, the volume and structure of the soil are initially retained because the skeleton of the coarser soil grains still support one another. The density of the earth decreases because the pore space increases. The seepage of water increases because the porosity also increases the permeability . Stability can suddenly decrease and there is a risk of sudden collapse, for example of dam structures.

A distinction is made between internal, external and contact suffusion depending on the location of the suffusion symptoms:

  1. The inner suffusion takes place inside the soil. It only lasts for a short time, and the transport routes of the moving particles are short if it is not caused or maintained by external suffusion or contact suffusion.
  2. The outer suffosion takes place on the free surface and is independent of the direction of the underground water flow. It creates or accelerates internal suffusion.
  3. In contact suffusion, the moving particles of a finer soil migrate into the pores of a coarser soil, where the process continues as internal suffusion.

Soil materials with a relatively large degree of non-uniformity and especially those with a grading curve with a failure grain are at risk of suffusion . Suffosion is counteracted with soil filters , observing the filter rules, and with geotextiles .

See also

The similarly written suffusion is a blood underflow, also popularly known as a bruise.

Earlier - and in English - the spelling "suffossion" was also used. The word origin is Latin: suffossio, suffodere, suffossum = dig under something.

Individual evidence

  1. ↑ Dachroth Handbook of Building Geology 2002, p. 166
  2. ↑ http://en.wiktionary.org/wiki/suffossion
  3. ↑ http://dictionary.reference.com/browse/suffossion

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