An elastoplastic model for sand—structure interface behaviour

Ghionna, Vito Nicola; Mortara, Giuseppe

doi:10.1680/geot.52.1.41.40826

Cited by 11 publications

(21 citation statements)

References 19 publications

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“…4 for Toyoura sand), the net outcome is an increase in w L with increasing ó 9 v0 . This is consistent with observations from model plate pull-out tests by Garnier & König (1998) and constant normal stress interface shear tests by Ghionna & Mortara (2002). Fig.…”

Section: Resultssupporting

confidence: 92%

Analysis of the shaft resistance of non-displacement piles in sand

Loukidis

Salgado²

2008

Géotechnique

129

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The paper examines, using numerical modelling, the problem of the limit shaft resistance of non-displacement piles installed in sands. The modelling makes use of an advanced, two-surface-plasticity constitutive model. The constitutive model predicts the soil response in both the small-and the large-strain range, while taking into account the effects of the intermediate principal effective stress and of the inherent anisotropy of the sand. Finite element analyses of shearing along the pile shaft are performed in order to examine the development of limit unit shaft resistance and the changes in stress state around the shaft upon axial loading of the pile. Special focus is placed on the operative value of the lateral earth pressure coefficient when limit shaft resistance is reached. The analyses offer useful insights regarding the factors controlling the value of unit shaft resistance in sands. The simulations predict a significant build-up of horizontal effective stress for dense sands. Based on these simulations, we propose a relationship between the lateral earth pressure coefficient for use in the calculation of the limit shaft resistance of the pile and the initial density and stress state of the sand.

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Section: Resultssupporting

confidence: 92%

Analysis of the shaft resistance of non-displacement piles in sand

Loukidis

Salgado²

2008

Géotechnique

129

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“…Before starting the formulation of the cyclic model, a brief description is given of the previous interface model [28,29] in which the cyclic mechanism has been incorporated. The monotonic model is framed in the classical elastoplastic theory assuming the relative velocity vector ½' u u as the sum of an elastic part ½' u u e and plastic part ½' u u p :…”

Section: Interface Model For Monotonic Loadingmentioning

confidence: 99%

“…Figure 2 shows some comparison between experimental and predicted plastic functions. In the original formulation [29] the plastic surfaces were slightly curved while in the present work a linear form is assumed:…”

Section: Interface Model For Monotonic Loadingmentioning

confidence: 99%

“…The derivation of the complete flow rule requires the knowledge of the maximum dilatancy d max : From the experimental tests it is observed that the latter parameter is influenced by the value of the stiffness coefficient K; namely by the followed stress path. However, both data derived from CNL and CNS tests lay on a unique hyperbolic trend if plotted vs the normal stress s n when they are normalized with respect to the initial normal stress s n0 [29]:…”

Section: Interface Model For Monotonic Loadingmentioning

confidence: 99%

“…The work is based on a previous elastoplastic isotropic interface model [28,29] and is completed by introducing a second plastic mechanism, subjected to rotational hardening, into the isotropic one.…”

Section: Introductionmentioning

confidence: 99%

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A 2‐D constitutive model for cyclic interface behaviour

Mortara

Boulon

Ghionna

2002

Num Anal Meth Geomechanics

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SUMMARYThe paper concerns a 2-D constitutive model for interface behaviour between sand and solid inclusions under cyclic loading. The model is based on the experimental results obtained from laboratory direct shear interface tests conducted under both constant normal load (CNL) and constant normal stiffness (CNS) conditions. The model is formulated in terms of interface stresses and relative velocities and has been derived by extending an elastoplastic isotropic model previously formulated for monotonic loading to stress reversal paths. Such extension consists in adding to the isotropic hardening mechanism a kinematic rotational one defined by an inner conical surface rotating around the origin of the stress space. This allows one to store the memory of the previous stress and relative displacement history giving to the model the capability to analyse the interface behaviour under cyclic loading. After a brief description of the criteria governing the monotonic model, the paper describes in detail the features of the kinematic hardening. Finally, the predictions of the model are compared with the experimental results obtained from CNL and CNS interface tests.

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Prediction of the shaft resistance of nondisplacement piles in sand

Lashkari

2012

Num Anal Meth Geomechanics

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SUMMARYUsing pile segment analysis, the mobilized shaft resistance of axially loaded nondisplacement piles in sand is investigated here. It is accepted that the shaft capacity of piles constructed in granular soils is highly influenced by the mechanical behavior of soil-structure interfaces forming adjacent the piles skin. Adopting the thin interface layer as a load transfer mechanism, a simple but accurate critical state compatible interface constitutive model is introduced. After evaluation, the interface model in conjunction with the pile segment analysis is applied for the prediction of the shaft resistance mobilized in nondisplacement piles. The proposed approach takes into account the influences of pile diameter and surface roughness together with the effects of the surrounding soil density and stiffness on the mobilized shaft resistance. The performance of the proposed method is verified by comparing its predictions with the experimental data of various model piles covering wide ranges of length, diameter, roughness, and surrounding soil properties.

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An elastoplastic model for sand—structure interface behaviour

Cited by 11 publications

References 19 publications

Analysis of the shaft resistance of non-displacement piles in sand

Analysis of the shaft resistance of non-displacement piles in sand

A 2‐D constitutive model for cyclic interface behaviour

Prediction of the shaft resistance of nondisplacement piles in sand

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