Comportement non drainé de sable Hostun RF très lâche en consolidation anisotrope

Matiotti, R.; Ibraim, Erdin; Doanh, T.

doi:10.1051/geotech/1996075035

Cited by 3 publications

(2 citation statements)

References 6 publications

(7 reference statements)

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“…7, Canou et al, 1991). Des résultats similaires ont été obte nus dans le cadre de travaux plus récents (Matiotti et al, 1996), confirmant l'influence très défavorable d'un cisaillement initial sur l'initiation du phénomène.…”

Section: 2 Influence De L'anisotropie De Consolidationunclassified

“…Lors des essais de compres sion, la contrainte axiale est principale majeure, alors qu'elle devient contrainte principale mineure dans les essais d'extension. On constate généralement une réponse plus faible du matériau lors des sollicitations d'extension, avec un comportement volumique géné ralement plus contractant en extension qu'en compres sion (Dupla et al, 1995 ;Matiotti et al, 1996). On peut même observer, pour certains indices de densité inter médiaires, des différences qualitatives importantes, avec une réponse dilatante durcissante en compression et une réponse contractante de type liquéfaction en extension (De Gennaro et al, 1996 ;Benahmed, 2001, Fig.…”

Section: 2 4 Trajet De Chargement (Compression-extension)unclassified

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Instabilités de liquéfaction et phénomène de mobilité cyclique dans les sables

Canou¹,

Benahmed²,

Dupla³

et al. 2002

Rev. Fr. Geotech.

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We present in this paper the elementary mechanical behaviours which are responsible for sometimes very spectacular flow failures of saturated sand masses, known under the generic term of liquefaction. After a brief description of the mechanical behaviour of soils under monotonie loading, we describe the phenomenon known as « static » liquefaction, which is a specific instability characteristic of loose (contractant) sands submitted to monotonic undrained (or constant volume) loading. Then, the behaviour of sand under cyclic loading is examined, showing strong analogies with the monotonie case. Two distinct phenomena, which may be initiated under cyclic loading, are described, called cyclic mobility, characteristic of dilatant states and true liquefaction, characteristic of essentially contracting states. These phenomena are controlled by different mechanisms and, for a given sand, either one may be triggered and develop, in function of the initial conditions of the sand. Finally, elements are given on a possible general framework, which could allow to account, in the same state diagram, for the different undrained behaviours which may be observed under monotonie and cyclic loadings.

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Section: 2 Influence De L'anisotropie De Consolidationunclassified

Section: 2 4 Trajet De Chargement (Compression-extension)unclassified

Instabilités de liquéfaction et phénomène de mobilité cyclique dans les sables

Canou¹,

Benahmed²,

Dupla³

et al. 2002

Rev. Fr. Geotech.

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Undrained instability of very loose Hostun sand in triaxial compression and extension. Part 1: experimental observations

Doanh

Ibraim

Matiotti

1997

Mech. Cohes.-Frict. Mater.

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The undrained behavior of very loose Hostun RF sand in triaxial compression and extension tests is described. The samples are consolidated isotropically or anisotropically along constant effective stress ratio paths. Very loose sand exhibits partial liquefaction, deviator peak stress at relatively low to very low axial strain, gradual post‐peak stress reduction to a small residual value at large strains, sharp loss of effective mean pressure due to generation of large pore pressure and overall volume reduction. The instability line of Lade is examined in the case of extension tests and extended for anisotropic samples. It is shown that monotonic and anisotropic consolidation strongly influences the instability concept. A higher positive anisotropic consolidation level produces a greater slope of the instability line in compression and a reverse trend can occur in extension. Complex stress history can develop a fossilized instability line depending on the amount of axial strain attained. Effective strain ratio increment at peak has an asymptotic stabilization effect. © 1997 by John Wiley & Sons, Ltd.

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Simulating the effects of induced anisotropy on liquefaction potential using a new constitutive model

Tran

Wong

Dubujet

et al. 2013

Num Anal Meth Geomechanics

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The effects of induced anisotropy on the undrained behaviour of very loose and saturated sands have been a subject of intensive investigation, both experimentally and theoretically, by several authors in the past few years. This paper proposes an original constitutive model well-adapted to simulate the behaviour of sands subject to complex stress histories, in particular, the preloading cycle along the classical drained stress path in compression. The developed model belongs to the family of critical state models. Its construction is based on a few theoretical concepts taken from the theory of 'Bounding Surface Plasticity' developed among others by Y. Dafalias and Popov (1975), the 'Clay And Sand Model' (CASM) of H. Yu (2006), the CJS model (B. Cambou and K. Jafari (1988)) and the hyperelastic isotropic model of P. Lade (1987). To accurately simulate volume changes, which represent a key element in soil behaviour, a state-dependent dilatancy rule is proposed, which can account for the influences of stress and void ratio. The current void ratio depends implicitly on the irreversible strains already accumulated hence the strain history. A kinematic hardening is combined with an isotropic hardening, involving rotation and distortion of the bounding surface, in order to capture correctly the experimental observations. Comparisons of experimental results to numerical simulations show that the model is able to simulate with a good precision the major trends of undrained responses of loose and presheared sands. It predicts correctly rapid static liquefaction at small or null drained preloading, as well as the progressive transition to a completely stable behaviour typical of dense sands, while the sample is loose in reality. At intermediate to large amplitudes of preloadings, the model also predicts correctly the temporary stage of instability when the deviatoric stress decreases slightly before rising up again. Hardening modulus at current stress point. According to Bardet [49], the hardening modulus depends on the image stress point and the distance δ separating the later from the current stress point.

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Comportement non drainé de sable Hostun RF très lâche en consolidation anisotrope

Cited by 3 publications

References 6 publications

Instabilités de liquéfaction et phénomène de mobilité cyclique dans les sables

Instabilités de liquéfaction et phénomène de mobilité cyclique dans les sables

Undrained instability of very loose Hostun sand in triaxial compression and extension. Part 1: experimental observations

Simulating the effects of induced anisotropy on liquefaction potential using a new constitutive model

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