essai de rétention des particules du sol

OBS: Pour satisfaire les exigences du bon fonctionnement d'un filtre en génie civil, la filtrabilité du géotextile doit répondre à une double condition: rétention des particules des sols (éviter le lessivage); circulation de l'eau (éviter le colmatage).
OBS: Les critères de rétention d'un sol meuble sont définis dans le tableau 57 où le seul paramètre conduisant au choix du géotextile est le diamètre de filtration, c'est-à-dire la valeur O[indice 95], que l'on retrouve dans l'échelle de classification des géotextiles des recommandations du C.F.G. [Comité Français sur les Géotextiles] (...)

CONT: Soil retention test. One variation of this test is directed primarily toward the use of geotextiles as underwater silt curtains. The test device consists of two rectangular tanks which are placed end to end with slide gates facing one another. Between these two slide gates is the fabric specimen under test. The upstream tank (with the slide gate closed) is now filled with water that has a known amount of silt uniformly mixed in it. The gate valve at the exit end of the downstream tank is opened. The test begins by lifting up the slide gates on each side of the fabric and allowing the (turbid) water to pass through the fabric, which is acting as a submerged soil filter.... This test ... is aimed at the reduction in turbidity of rivers and streams during adjacent construction activities. The other variation of a soil retention test is directed toward the use of geotextiles as aboveground silt fences.