Soutenance de thèse – Dinh Minh TRAN “Suffusion susceptibility characterization by taking into consideration the context of engineering practice “. The composition of the jury and the abstract are detailed below.”

Dinh Minh TRAN soutiendra sa thèse le 8 décembre 2020 à 9h30 à l’IUT de Saint Nazaire sur le sujet suivant :

“Suffusion susceptibility characterization by taking into consideration the context of engineering practice “. The composition of the jury and the abstract are detailed below.”

Résumé :

Internal erosion processes in earth structures and their foundations may increase the failure risk of such structures. Suffusion, one of the main internal erosion processes, selectively erodes the fine particles that move through the coarser grains. Thus to ensure the safety assessment of these structures, it is important to characterize the soil suffusion susceptibility. Most of suffusion tests described in literature were performed under vertical flow, whereas the flow in earth structures can be horizontal as well. To study the potential influence of the flow direction, a new apparatus is developed and a series of suffusion tests is carried out. Two cohesionless soils which slightly differ from each other in their gradations are tested. The results show that both soils are slightly more resistant under horizontal flow and they highlight the combined effect of the hydraulic loading and the gravity on the detached particles. For specimens constituted by two layers of each soil and under both flow directions, the suffusion susceptibility is mainly influenced by the more erodible soil when the flow is parallel to the soil horizons. While the suffusion susceptibility mainly depends on the more resistant soil when the flow is perpendicular to soil horizons. Moreover a method is proposed to select the pore opening size of the downstream filter in order to avoid any underestimation of the soil suffusion susceptibility. Due to the great length of earth structures, and the heterogeneity of soils, it is important to optimize the experimental campaigns, thanks to a statistical analysis. From the database of suffusion tests of our team and complementary tests performed on seven soils, an estimation of the erosion resistance index is proposed, which is based on four parameters, which are quite easy to measure.

Rapporteurs :

Pierre BREUL, Professeur, Université Clermont Auvergne, Clermont-Ferrand
Philippe REIFFSTECK, Directeur de recherche HDR, Université Gustave Eiffel, Marne la Vallée

Examinateurs :

Nadia BENAHMED, Chercheur, INRAE, Aix en Provence
Eric VINCENS, Professeur, École Centrale de Lyon

Directeur de thèse :

Didier MAROT, Professeur, Université de Nantes

Co-directeur de thèse :

Fateh BENDAHMANE, Maître de conférences, Université de Nantes