Sedimentary and hydraulic characterization of a heterogeneous glaciofluvial deposit: Application to the modeling of unsaturated flow

• Published in: Engineering Geology
• Main Authors: Goutaland, David, Winiarski, Thierry, Lassabatère, Laurent, Dubé, J.S., Angulo-Jaramillo, Rafaël
• Other Authors: Departement Laboratoire de Clermont-Ferrand, Centre Etude Technique de l'équipement de lyon, Équipe 5 - Impacts des Polluants sur les Écosystèmes, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Geotechnical and Geoenvironmental Engiineering (LG2), Ecole de Technologie Supérieure Montréal (ETS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: Stormwater and infiltration basin; Glaciofluvial deposit; Lithofacies; Hydrofacies; Vadose zone; Preferential flow; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Iceland
• Online Access: https://hal.science/halsde-00921324; https://doi.org/10.1016/j.enggeo.2013.09.006

International audience Flows in the unsaturated zones of alluvial deposits are often poorly understood at the scale of structures such as stormwater infiltration basins. The heterogeneous nature of the sediment inherent to this type of formation can lead to preferential flows. The difficulty of quantifying them lies in obtaining hydrodynamic parameters representative of the soil structure in-situ, when the latter is inaccessible. This study proposes a method of estimating the hydrodynamic parameters of the lithofacies composing a glaciofluvial deposit (east Lyon, France) and their integration in a 2D flow model to model flow in the unsaturated zone. The approach developed comprises a sedimentological study based on the Miall code, carried out to determine the analogy between the lithofacies of the study site and those of two glaciofluvial reference sites currently in the process of formation (Chamonix, France; Breidamerkurjökull, Iceland), thereby permitting easy access to all the lithofacies identified on the study site. The water retention and hydraulic conductivity curves were obtained on the reference sites by using Beerkan type infiltration tests for finely textured materials, completed by the Arya and Paris model and data from the literature for coarser materials. Thus hydrofacies corresponding to all the lithofacies were charac- terized. These hydrofacies were used to model a drainage phase on the study site at the scale of a trench (13.50 m long × 2.50 m deep). The model highlighted the importance of the role played by the spatial distribution of hydrofacies on flows, with a pronounced capillary barrier effect of the very coarse lithofacies and a sand lens leading to funneled flows. By assuming that there is a direct link between the sedimentary lithological heterogeneity and the unsaturated hydrodynamic properties of the materials composing its different structures, it was possible to perform a detailed hydrodynamic characterization of the unsaturated zone that could then be used to model flows, and ...