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Communication Dans Un Congrès Année : 2012

Internal erosion of cohesive soils: laboratory parametric study

Nadia Benahmed
Stéphane Bonelli

Résumé

Internal erosion by piping is one of the main causes responsible of accidents and failures of earth structures such as embankment dams and dykes. This phenomenon occurs when concentrated leak develop in pre-existing defects in the earth fill such cracks and micro fissures, discontinuities, hydraulic fracture, channels, roots and burrows. It involves the removal of soil particles from the subsurface of these defaults to an exit point, leading to the formation and the evolution of a continuous “pipe” between the upstream and the downstream side. A new experimental device has been developed to carry out hole erosion tests in laboratory in order to better understand the mechanism of internal erosion process of soil. A series of hole erosion tests were carried out under constant flow rate in order to quantify the critical shear stress (Tau_c) and the coefficient of piping erosion (ker) of soils. Parametric studies were conducted on Kaolinite and Hostun sand/Kaolinite mixture. The key parameters investigated in this study were effects of moisture content, compaction energy and percentage of fines. The experimental results show that these parameters play a key role on the erosion characteristics (Tau_c and ker). A numerical piping model has been developed from equations of diphasic flow with diffusion and the equation of jump with erosion to interpret the hole erosion tests.
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Dates et versions

hal-00762192 , version 1 (06-12-2012)

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Nadia Benahmed, Stéphane Bonelli. Internal erosion of cohesive soils: laboratory parametric study. 6th International Conference on Scour and Erosion, Aug 2012, Paris, France. 8 p. ⟨hal-00762192⟩

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