Flowing sediments such as debris and liquefied soils could exert a tremendous amount of force as they impact objects along their paths. The total impact force generally varies with slope angle, velocity at impact, and thickness of the flowing sediment. Estimation of the impact force of flowing sediments against protective measures such as earth retaining structures is an important factor for risk assessment. In this paper, we conduct small-scale laboratory physical modeling of sand flow at different slopes and measure the impact force exerted by this material on a fixed rigid wall. We also conduct numerical simulations in the Eulerian framework using computational fluid dynamics algorithms to analyze and reproduce the laboratory test results. The numerical simulations take into consideration the overtopping of the wall with sand, which influenced the measured impact force-time history responses. In addition, the numerical simulations are shown to capture accurately the change of the impact force with slope angle. Finally, the modeling approach conducted in this study is used to estimate the quasi-static force generated by the sediment as it comes to rest on the wall following impact.

A cyclic elasto-plastic constitutive model based on a non-linear kinematic hardening rule for sand is proposed. Three points are incorporated into the model: a new flow rule, a cumulative strain-dependent characteristic of the plastic shear modulus and a fading memory characteristic of the initial anisotropy of the constitutive model. In order to verify its effectiveness, the proposed model was evaluated by means of the results of a series of hollow-cylinder torsional shear tests with and without an initial shear stress after isotropic and anisotropic consolidation. The liquefaction strength curve, the effective stress path and the stress—strain relation during cyclic loading are well reproduced by the proposed model. KEYWORDS: constitutive relations; liquefaction; plasticity; repeated loading; sands. Nous proposons ici un modèle constitutif élastoplastique cyclique basé sur une règle de durcissement cinématique non linéaire du sable. Trois points sont incorporés dans le modèle: une nouvelle règle d'écoulement, une caractéristique cumulative dépendant de la déformation du module de cisaillement plastique et une caractéristique de mémoire évanescente de l'anisotropie initiate du modèle constitutif. Afin de vérifier son efficacité, nous évaluons le modèle proposé en utilisant les résultats d'une série d'essais de cisaillement torsionnel cylindrique creux avec et sans contrainte tangentielle initiale après consolidation isotrope et anisotrope. La courbe de résistance à la liquéfaction, le chemin de contrainte effective tout comme la relation contrainte-déformation pendant le chargement cyclique sont bien reproduits par le modèle proposé.

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