Geotextile filter criteria

Table 12.1 Geotextile filter criteria for steady-state flow...

According to the filtration function, a geotextile filter must be able to retain fine particles of base soil (retention criterion) and avoid the development of excessive pore water pressure on a soil geotextile interface (ie, fi ee flow of liquid through the geotextile plane) (permeabihty criterion). 

The filtration opening size and PSD are important in the design retention criterion that refers to geotextile filter capacity to retain the fine particles of base soil. It is commonly expressed as (Eq. [8.5]) ... 

The permeability criterion of the filter system refers to the capacity of the geotextile filter to guarantee free liquid flow across the filter s plane. For this function, geotextile cross-plane permeability or permittivity is necessary for the design, and sometimes also thickness and porosity. 

The permeability criterion (in terms of the pore pressure requirement) is generally verified for geotextile filters owing to their high permeability and limited thickness (Pahneira and Fannin, 2002). Therefore, attention must be directed to the soil—filter interface phenomena (blinding and clogging) by means of laboratory tests, especially for unstable granular sods. 

Moraci, N., 1996. A new design criterion for geotextiles as filters. In Proc. Geofilters 96. Montreal, Canada, pp. 203—213. 

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