ETUDE NUMERIQUE DES PRESSIONS PASSIVES APPLIQUEES SUR UN BLOC D’ANCRAGE RIGIDE NUMERICAL STUDY OF PASSIVE EARTH PRESSURES AGAINST RIGID ANCHOR BLOCK

L’étude des pressions passives du sol joue un rôle très important, dans le cas des problèmes d’interaction sol-structure. Plusieurs paramètres géométriques et mécaniques influent sur l’intensité et la distribution des pressions passives; lorsque les blocs d’ancrage des ouvrages de soutènement sont indépendants et ne forment pas un corps continu, le sol n’est pas en équilibre à deux dimensions. Les blocs d’ancrage mobilisent la résistance passive du sol d’une manière tridimensionnelle. Cette étude vise, d’une part la présentation de quelques méthodes utilisées pour le dimensionnement des blocs d’ancrage, et l’estimation numérique des pressions passives sur un bloc rigide et isolé, soumis à un mouvement de translation dans un sol frottant; d’autre part l’évaluation de l’influence de la largeur d’un bloc sur les pressions passives, en utilisant le code FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions). Les valeurs numériques obtenues par cette étude sont comparées aux résultats issus par l’approche cinématique de l’analyse limite

UNDRAINED BEARING CAPACITY OF EMBEDDED STRIP FOOTINGS UNDER VERTICAL AND HORIZONTAL LOADS

This paper is concerned with the undrained bearing capacity of embedded strip footing under inclined loading (i.e. combined vertical and horizontal). A series of numerical computations using the finite-difference code Fast Lagrangian Analysis of Continua (FLAC) was carried out to evaluate the failure envelopes in vertical force – horizontal force (V-H) plane, using both probe and swipe analyses. The adopted approach involves a numerical solution of the equations governing elasto-plastic soils. The soil is modeled by an elasto-plastic model with a Tresca criterion. The results are presented in terms of the failure envelope in vertical and horizontal loading plane. 

NUMERICAL STUDY OF DEPTH FACTORS FOR UNDRAINED LIMIT LOAD OF STRIP FOOTINGS

Current studies of bearing capacity for shallow foundations tend to rely on the hypothesis of an isolated footing lying on the ground surface. In practice a footing never lies on the ground surface; it is mostly embedded at a depth D below the ground surface. This paper focuses on a numerical study using the finite-difference code Fast Lagrangian Analysis of Continua(FLAC),to evaluate the bearing capacity of embedded strip footings. The effect of the embedment is estimated though a depth factor, defined as a ratio of the bearing capacity of a strip footing at a depth Dto that of a strip footing at the ground surface. The results presented in this paper show that the size and shape of the shear zone and displacement field defining the undrained capacity of shallow foundations under centred vertical loading are dependent on embedment rati

NUMERICAL ANALYSIS OF SHALLOW FOUNDATIONS ON PURELY COHESIVE SOIL UNDER ECCENTRIC LOADING

The classical theory of the bearing capacity of shallow foundations is based on the effective width approach for the case of vertical eccentric loading. This method stipulates that the area of the foundation, used in the calculation of the bearing capacity, is equal to the area of a fictive foundation on which the loading is applied at the center. This paper evaluates the performance of this approach in predicting the ultimate load of the footing. A numerical analysis is performed to estimate the undrained bearing capacity mobilized in a purely cohesive soil under a strip footing, using the finite difference code FLAC3D (Fast Lagrangian Analysis of Continua in 3 dimensions). The results of this analysis show that the effective width approach provides a good approximation of the bearing capacity for this kind of problems

ETUDE NUMERIQUE DU FACTEUR DE PORTANCE NΓ POUR UNE FONDATION FILANTE ET CIRCULAIRE NUMERICAL STUDY OF BEARING CAPACITY FACTOR NΓ OF STRIP AND CIRCULAR FOOTING

Le problème d’évaluation de la capacité portante est largement étudié en tenant compte des différents paramètres géométriques et mécaniques. Les calculs sont basés sur la méthode d'équilibre limite, la méthode de ligne de glissement et la méthode d'analyse limite. Malgré la diversité dans les méthodes de calcul, l’écart entre les valeurs des facteurs de portance est très large surtout pour les grandes valeurs de l'angle de frottement et l'angle d'interface. Cet article vise d’une part l’estimation numérique du facteur de portance Nγ pour des fondations filante et circulaire sous une charge verticale centrée, en utilisant le code FLAC2D (Fast Lagrangian Analyses of Continua in 2D), et d’autre part la comparaison de ces résultats numériques avec les résultats des publications récentes. The bearing capacity evaluation problem is largely studied by taking into account various geometrical and mechanical parameters. The use of the various approaches (limit equilibrium, limit analysis, numerical computation and experimentally studies) makes it possible to enrich the comprehension of the footing behaviour. This paper is concerned the numerical estimation of the bearing capacity factor Nγ of a strip and circular footing in vertical load, using the code FLAC2D (Fast Lagrangian Analyses of Continua in 2D). The results given by the present numerical analysis are compared with the results of recent publications

Capacité portante des fondations superficielles avec et sans l'hypothèse de superposition

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Etude numérique de la capacité portante d'une fondation filante au bord d'une pente

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Coefficients de forme pour la capacité portante d'une semelle circulaire sur un sol frottant

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Numerical study of the bearing capacity for two interfering strip footings on sands

International audienceCurrent studies of bearing capacity for shallow foundations tend to rely on the hypothesis of an isolated footing. In practice a footing is never isolated; it is mostly in interaction with other footings. This paper focuses on a numerical study using the finite-difference code Fast Lagrangian Analysis of Continua (FLAC), to evaluate the bearing capacity for two interfering strip footings, subjected to centered vertical loads with smooth and rough interfaces. The soil is modeled by an elasto-plastic model with a Mohr-Coulomb yield criterion and associative flow rule. The interference effect is estimated by efficiency factors, defined as the ratio of the bearing capacity for a single footing in the presence of the other footing to that of the single isolated footing. The efficiency factors have been computed individually to estimate the effects of cohesion, surcharge, and soil weight using Terzaghi's equation, both in a frictional soil with surcharge pressures and in a cohesive-frictional soil with surcharge pressures. The results have been compared with those available in the literature

Etude numérique de l’effet d’une cavité sur la capacité portante d’une fondation superficielle

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