Blinding forms when fines pile up against the upstream face of the fabric instead of passing through or bridging into a stable filter. It is most common with tight wovens and heat-bonded fabrics in silty or gap-graded soils, and it can cut flow by orders of magnitude. A more open fabric, checked with a gradient ratio test, is the usual defense.
Slit film blinded off against that silt in a week, and now water is backing up behind the wall.
Also heard as
- surface blinding
Related terms
Clogging
Gradual loss of flow through a geotextile as soil particles or deposits lodge inside its pores.
Gradient ratio
Laboratory ratio that shows whether a soil and geotextile pair is starting to clog under steady seepage.
Slit film
Woven geotextile made from flat polypropylene tapes cut from extruded film, strong and cheap but a poor filter.
Filtration
Letting water pass across a geotextile while holding back the soil particles it carries.