Résumé

Stability analyses of embankment dams are commonly carried out under effective stress with the strengths measured on perfectly saturated soils. Many embankments since their impounding have piezometric heads folded down by the central filter and stabilized displacements. This long-term situation suggests that the margin of safety is sufficient. However, some of them have safety factors below the current steady state threshold, F=1.5. The question raised by this paradox (the combination of good behaviour and a safety factor below current standards) is whether good behaviour does not come from unsaturation, which would provide stabilizing capillary cohesion. To answer this question, recent research on unsaturated soils is used. Three models describing unsaturated soil are presented. They are all based on the application of the principle of effective stress in the field of unsaturation. These are, in chronological order of appearance, the model presented by Taibi in his PhD thesis (1994), supervised by Professors Biarez and Fleureau, Lu's model (2014) which builds upon generalizes Van Genuchten's work and the model recently published by T. Dubreucq in the ANR TerreDurable report (2019). These three models are then applied to a case study. This involves characterizing the embankment of a canal in fine soil. Each model then determines a possible range of capillary cohesion in the material. The results of the three models are presented and compared with each other. Then the variability of the soil in place, measured by investigations, is analysed. It is taken into account by knowing the ranges of physical properties (Atterberg limits, density, water content). Finally, proposals for the choice of the characteristic value of cohesion open up prospects for the application of these approaches for future stability studies of existing embankments.

Information

Item Type:	Conference
Divisions:	» Laboratoire de Gestion, Maintenance et Réhabilitation Des Equipements et des Infrastructures Urbaines » Faculté des Sciences et de la Technologie
ePrint ID:	2902
Date Deposited:	2022-01-29
Further Information:	Google Scholar
URI:	https://www.univ-soukahras.dz/fr/publication/article/2902

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