Geotextiles in Embankment Dams - Association of State Dam Safety ...

Geotextiles in Embankment Dams2.5 GeonetsGeonets (figs. 2.7 through 2.9) have also been called a “geotextile related product” inthat they consist of coarse sets of parallel extruded strands or ribs that intersect at aconstant angle (between 45 and 90 degrees) and are thermally bonded at theintersections. Geonets range in thickness from 5 to 9 mm. ASTM (2005) defines ageonet as “a geosynthetic consisting of integrally connected parallel sets of ribsoverlying similar sets at various angles for planar drainage of liquids or gases.” One,two or three sets of ribs create a network of channels which can convey fluids intheir plane with minimal compression under load. Geonets are predominantlymanufactured of HDPE. Geonets are also associated with geotextiles which aretypically nonwoven and melt bonded to the geonet surface. Geotextiles associatedwith geonets are used as a filter and/or separator when interfacing with soils.Figure 2.7.—Photograph of a bi-planar geonet. It is made from two layers of polymericstrands or ribs.26