Numerical modeling framework for soil-geosynthetics interaction problems

Numerical modeling of soil-structure interaction problems involving flexible or soft geosynthetic inclusions and large deformation is known to be challenging, especially in the presence of nearby structures. This thesis is devoted to developing a numerical modeling framework for the analysis of soil-geosynthetic interaction problems. It reports the results of both 2D and 3D analyses with explicit modeling of the geometry and material behavior of geosynthetics and the surrounding backfill. The numerical results are validated using existing laboratory experimental data. Two types of geosynthetics that are commonly used in geotechnical engineering projects are considered using the proposed numerical framework; EPS geofoam and geogrid. A numerical procedure for modeling the short-term response of EPS geofoam is first developed and validated for three different EPS geofoam materials. To examine the performance of such model in analyzing complex interaction problems, a laboratory experiment that involves a rigid structure buried in granular material with EPS geofoam inclusion is simulated using a series of 2D finite element analysis. The role of geofoam material, geometrical properties, and configuration on the reduction of earth loads acting on buried structures are investigated. Results showed that the introduction of EPS geofoam block immediately above the structure has a significant effect on the contact pressure distribution particularly on the upper wall of the structure. The rest of the thesis is devoted to introducing a numerical framework that is suitable for the three-dimensional analysis of applications involving soil-geogrid interaction. The geogrid response is investigated under both unconfined and soil-confined environments using different loading conditions (e.g. vertical foundation loading and pullout loading). The proposed FE approach has proven to be efficient in capturing the 3D response of the geogrid, the surrounding backfill, and the geogrid-backfill contact interaction. %%%%La modelisation numerique des problemes d'interaction sol-structure impliquant des inclusions geo-synthetiques flexibles ou souples et de grande deformation est reconnue pour sa complexite, surtout en presence de structures rigides a proximite. Cette these a pour objectif majeur l'elaboration d'un concept de modelisation numerique pour les problemes d'interaction sol-geo synthetiques. Il fait etat des resultats des analyse 2D et 3D avec la modelisation explicite de la geometrie et des details des materiaux de la structure geosynthetique et le remblai environnant. Deux types de geo synthetiques qui sont couramment utilises dans les projets geotechniques sont consideres en utilisant le cadre numerique proposee; geogrille et Polystyreene expanse (PSE) Geofoam. Une procedure numerique de modelisation du comportement a court terme de Geofoam PSE soumis a une charge uni axiale de compression est d'abord developpe et valide pour trois materiaux de Geofoam PSE differents. Pour examiner les performances de ce modele dans l'analyse des…