首页|A Hydraulic Gradient and Stress-Controlled Erosion Apparatus for Assessing Soil Internal Erosion
A Hydraulic Gradient and Stress-Controlled Erosion Apparatus for Assessing Soil Internal Erosion
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NETL
NSTL
Amer Soc Testing Materials
Among the four dominant mechanisms of internal erosion, suffusion appears as one of themost complex. It is indeed the result of the combination of three processes: dislodgementof fine particles, transport of them, and filtration of some fluidized fine particles. These processesdepend on the soil’s stress state and on the hydraulic gradient path. Thus, to ensure therepeatability of the suffusion test and to study with accuracy the influence of the aforementionedparameters, a new apparatus was developed. This apparatus is designed to test specimensunder a vertical downward flow in hydraulic gradient controlled condition whilecontrolling the confining pressure and the stress deviator, which can be either positive or negative.Ten tests on one cohesionless soil were performed in triaxial conditions, with the samemean effective stress and four different values of stress deviator. To compare with conventionalsuffusion results, one test is also performed in rigid wall conditions. For all performedtests, the same hydraulic gradient path was applied and particular attention is paid to the repeatability,which implies control of each test step. At the end of each test, the specimen wasdivided into four layers to measure post-suffusion grain size distributions. The time evolutionsof the hydraulic conductivity and the erosion rate permit to identify four different phases. Eachphase is characterized by two methods: one based on the hydraulic gradient and the secondbased on the expended energy by the fluid. The results show the great influence on the suffusionkinetics of the preferential flow paths, which localize in the body of the specimen intriaxial conditions and on the circumference in rigid wall ones. Under a constant mean effectivestress, the effect of the stress deviator on the suffusion kinetics appears limited, for the testedsoil and shear stress ratios.
Didier Marot、Bikram Oli、Fateh Bendahmane、Rachel Gelet、and Philippe Leroy
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Nantes Université, École CentraleNantes, Centre National de laRecherche Scientifique, Institut deRecherche en Génie Civil etMécanique, UMR 6183, 58 RueMichel Angle, Boite Postale 420,F-44606 Saint-Nazaire Cedex,France
NETL
NSTL
Amer Soc Testing Materials
