Cress Help - Structures - Structures protecting against waves - Other materials for slope protection - C40.1

Geotextiles

Erosion of soil can be prevented by using geometrically sand tight geotextiles with openings smaller than the diameter of the grains of the ground that is to be protected. Sometimes this is not possible, for example with very fine sand, silt or clay. In that case geometrically open geotextiles are needed.

Equations used:

Static conditions in non-cohesive soil:

    equation 1

    equation 2

Dynamic conditions in non-cohesive soil:

    equation 3

Static and dynamic conditions in cohesive soil:

    equation 4

in which:

  • Dbx: diameter of a grain of the basic material for which x weight percentage is smaller [m]
  • O90: diameter of the openings in the geotextile is equal to the average diameter of the standardised sand fraction, of which 90% remains lying on the geotextile after dry sieving [m]

 

Reference:
[a] Design criteria for geotextiles on sand and cohesive soils, E. Berendsen and G.M. Smith