SELECTION OF GEOTEXTILE FILTERS WRAPPED AROUND PIPES IN PAVEMENT EDGEDRAINS

Geotextile filters are rapidly replacing graded granular filters as th e standard practice in geotechnical design. This paper describes a lab oratory study on filtration behaviour of three different kinds of geot extile, in order to select the most suitable fabric for a particular f ield application of pavement edge drains. Based on long-term performan ce studies of the geotextile filters wrapped around drain pipes, reten tion and permeability criteria for selection of the geotextile under a compacted backfill have been recommended. Regarding the clogging resi stance criterion, it has been concluded that instead of choosing a geo textile based on its indicative pore size, it would be advisable to co nduct a gradient ratio test at equilibrium flow conditions for studyin g the clogging resistance of geotextiles.