Fines carried by seepage get trapped within the fabric, reducing permittivity over time, and chemical or biological deposits do the same in leachate and iron-rich groundwater. Some reduction is normal as a stable filter forms, but heavy clogging builds water pressure behind walls and starves drains. Designers guard against it with opening size criteria, permittivity margins and gradient ratio tests.
Toe drain quit flowing after two years, and the fabric we dug up was clogged with iron ochre.
Also heard as
- clog
Do not mix it up with
- Blinding: Blinding is a skin of particles sealing the surface of the fabric, while clogging is particles lodged inside it.
Related terms
Blinding
Sealing of a geotextile surface by a thin layer of fine particles that blocks flow across it.
Gradient ratio
Laboratory ratio that shows whether a soil and geotextile pair is starting to clog under steady seepage.
Filtration
Letting water pass across a geotextile while holding back the soil particles it carries.
Piping
Soil particles washing through a filter or out of an embankment, leaving voids and channels behind.