Long-term protection efficiency of nonwoven polypropylene geotextiles

European Standard EN ISO 13719:2002 specifies an index test used to determine the efficiency with which a geotextile will protect a geosynthetic barrier against the mechanical long term effects of static point loads. Laboratory tests were conducted on 16 nonwoven needle-punched polypropylene geotextiles (mass per unit area 202 g/m(2)-1,406 g/m(2), thickness 1.63 mm-10.06 mm) representing six different manufacturers and made of staple fibers or continuous filament. Based on local strain measurements, the protection efficiency values of the geotextiles were found to range between 25.0x10(3) and 66.7x10(3) kN/m(2). Good linear correlations (R-2=0.85-0.88) were obtained between protection efficiency and mass per unit area, average tensile strength and static puncture strength. Geomembrane protection under high external loads (1200 kPa) requires use of relatively heavy geotextiles (over 1,500 g/m(2)). Selection of an appropriate geotextile depends on the anticipated magnitude of the external load and on the specified allowable geomembrane deformation.