Internal Flow Effects on Isotropic Confined Sand-Clay Mixtures

Didier Marot (1) , Fateh Bendahmane (1) , Frédéric Rosquoët (1) , Alain Alexis (1)

1 GeM - Institut de Recherche en Génie Civil et Mécanique

Under the effect of internal flows, a liner can undergo a washing out of particles, which modifies the particle size distribution and affects hydraulic, chemical and mechanical characteristics. This paper discusses the effects of internal flows on sand/kaolin mixture, in terms of rate of erosion and modification of the hydraulic conductivity. A parametric study is conducted with a specific device that consists of three modified triaxial cells. These cells allow isotropically consolidating and confining specimens, they prevent a parasitic flow and survey large deformations of specimen. The tests reveal that suffusion of clay is accompanied by a clogging in the specimen that induces a drop in hydraulic conductivity. For high gradients the erosion of clay is accompanied by the backward erosion of sand and finally the specimen collapses. The erosion rate then depends on the values of the different parameters considered (hydraulic gradient, clay content and filter pore opening size).

Mots clés: Backward erosion; hydraulic conductivity; internal erosion; rate of erosion; sand-clay mixture; suffusion

Domaines: Mécanique [physics.med-ph]; Matériaux

Didier Marot, Fateh Bendahmane, Frédéric Rosquoët, Alain Alexis. Internal Flow Effects on Isotropic Confined Sand-Clay Mixtures. Soil and Sediment Contamination, 2009, 18 (3), pp.294-306. ⟨10.1080/15320380902799524⟩. ⟨hal-01006992⟩