The paper describes a numerical model that was developed to simulate the response of three instrumented, full-scale, geosynthetic-reinforced soil walls under working stress conditions. The walls were constructed with a fascia column of solid modular concrete units and clean, uniform sand backfill on a rigid foundation. The soil reinforcement comprised different arrangements of a weak biaxial polypropylene geogrid reinforcement material. The properties of backfill material, the method of construction, the wall geometry, and the boundary conditions were otherwise nominally the same for each structure. The performance of the test walls up to the end of construction was simulated with the finite-difference-based Fast Lagrangian Analysis of Continua (FLAC) program. The paper describes FLAC program implementation, material properties, constitutive models for component materials, and predicted results for the model walls. The results predicted with the use of nonlinear elastic-plastic models for the backfill soil and reinforcement layers are shown to be in good agreement with measured toe boundary forces, vertical foundation pressures, facing displacements, connection loads, and reinforcement strains. Numerical results using a linear elastic-plastic model for the soil also gave good agreement with measured wall displacements and boundary toe forces but gave a poorer prediction of the distribution of strain in the reinforcement layers.Résumé : Cet article décrit un modèle numérique qui a été développé pour simuler la réponse de trois murs de sol à pleine échelle, instrumentés, armés de géosynthétique et soumis à des conditions de contraintes de travail. Les murs ont été construits avec un parement de colonnes d'unités modulaires solides en béton et un remblai de sable propre uniforme sur une fondation rigide. L'armature du sol comprenait différents arrangements de matériel d'armature en faible géogrid biaxial de polypropylène. Les propriétés du matériau de remblai, la méthode de construction, la géométrie du mur et les conditions aux frontières étaient par ailleurs nominalement les mêmes pour chaque structure. On a simulé la performance des murs d'essais jusqu'à la fin de la construction au moyen du programme FLAC basé sur les différences finies. Cet article décrit l'implémentation du programme FLAC, les propriétés du matériau, les modèles constitutifs pour les matériaux impliqués et les résultats prédits pour les murs modèles. On montre que les résultats prédits au moyen des modèles non linéaires élastiques plastiques pour le sol de remblai et les couches d'armature sont en bonne concordance avec les forces mesurées à la pointe de la fondation, les pressions verticales sur la fondation, les déplacements du parement, les charges aux joints, et les déformations des armatures. Les résultats numériques obtenus au moyen d'un modèle linéaire élasto-plastique pour le sol a aussi donné une bonne concordance avec les déplacements mesurés du mur et les forces à la pointe, mais ont donné une mauvaise prédiction de la distribution ...

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The paper reports results from numerical experiments that were carried out to investigate the influence of reinforcement stiffness, reinforcement length, and base boundary condition on the seismic response of an idealized 6 m high geosynthetic-reinforced soil retaining wall constructed with a very stiff continuous facing panel. The numerical models were excited at the foundation elevation by a variable-amplitude harmonic motion with a frequency close to the fundamental frequency of the reference structure. The two-dimensional, explicit dynamic finite difference program Fast Lagrangian Analysis of Continua (FLAC) was used to carry out the numerical experiments. Numerical results illustrate that the seismic response of the wall is very different when constructed with a base that allows the wall and soil to slide freely and when the wall is constrained to rotate only about the toe. Parametric analyses were also carried out to investigate the quantitative influence of the damping ratio magnitude used in numerical simulations and the effects of distance and type of far-end truncated boundary. The response of the same wall excited by a scaled earthquake record was demonstrated to preserve qualitative features of wall displacement and reinforcement load distribution as that generated using the reference harmonic ground motion applied at 3 Hz. The lessons learned in this study are of value to researchers using dynamic numerical modeling techniques to gain insight into the seismic response of reinforced wall structures.

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