Instabilité post-sismique des digues. Une approche en déplacements

Résumé

L'article propose une récapitulation des observations des désordres produits dans les digues par des séismes, en vue de mieux connaître les mécanismes de déformation et de rupture de ces ouvrages. Puis, une méthode de calcul en déplacement est proposée, qui vise à décrire une cinématique de rupture post-sismique initiée par des pressions interstitielles. Le principe du calcul est exposé. Un exemple est commenté.

Impacts of the construction of Vridi channel on the coastal sediment stocks located between Abidjan and Jacqueville (Côte d’Ivoire)

This work is a contribution to the knowledge of sediments and morphology changes of the coast between Abidjan and Jacqueville. The method used for this purpose is based on processing, analysis of topographic profiles and sand sampling collected on the field during successive surveys which were conducted from the year 1998 to 2008. The approach resulted in the identification of a sedimentary deficit of -2500 m3 in Port-Bouët and a positive sediment budget +2300 m3 in Jacqueville. This feeding engrossment causes a coastline progradation of 13.5 m. Sediments study highlights the various sediment stocks on both sites. On one hand, there is a stock mainly composed of coarse and polished material in Jacqueville indicating a long water way carriage, and on the other hand, there is a main stock of sub-angular to angular and very coarse materials in Port-Bouët showing the closeness of the purveying source. This study highlights the effects of protection works realized on the port channel on the distribution of facies between Jacqueville and Port-Bouët.

Keywords: Erosion and accretion; Sediment budget; Beach Profile; Port-Bouët; Jacqueville; Côte d’Ivoire.