BLINDING AND CLOGGING OF A NONWOVEN GEOTEXTILE

TATSUAKI NISHIGATA, R. JONATHAN FANNIN and YOGINDER P. VAID

ABSTRACT The filtration compatibility of soil-geotextile systems has been assessed experimentally in the laboratory with the gradient-ratio test. A nonwoven geotextile was used against a variety of model soils that were prepared from glass beads. They exhibited a range of fines content, in both gap-graded and broadly-graded size distributions. Filter blinding and clogging, if it happens, occurs within hours of initiating unidirectional flow. The zone of soil above the geotextile that is influenced is relatively thin. In gap-graded soils, the movement of fine particles appears to occur at a condition of D₈₅/D₁₅> 8. A new dimensionless index is proposed to quantify the internal stability of gap-graded soils.

Key words: erosion, geotextile, sand, seepage, silt (IGC: E7/D4/H7)