Flow liquefaction instability prediction using finite elements

Mohammadnejad, T.; Andrade, José E.

doi:10.1007/s11440-014-0342-z

Cited by 21 publications

(9 citation statements)

References 23 publications

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“…It is widely accepted that liquefaction is an instability and it can occur under static or dynamic conditions. Several researchers have shown the unstable behavior of the material and proposed instability criteria for defining the onset of soil liquefaction (Lade, 1994;Borja, 2006;Zhang and Wang, 2012;Andrade et al, 2013;Mohammadnejad and Andrade, 2015;Najma and Latifi, 2017). Throughout this work, the levee's stability is calculated based on Hill's instability criterion of the second order work (Hill, 1958;Hamadi et al, 2008;Buscarnera and di Prisco, 2012).…”

Section: Background Of Dynamic Liquefaction Analysismentioning

confidence: 99%

Liquefaction analysis and damage evaluation of embankment-type structures

Rapti

López-Caballero

Modaressi-Farahmand-Razavi

et al. 2018

Acta Geotech.

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The increasing importance of performance-based earthquake engineering analysis points out the necessity to assess quantitatively the risk of liquefaction of embankment-type structures. In this extreme scenario of soil 2 Ioanna Rapti et al. liquefaction, devastating consequences are observed, e.g. excessive settlements, lateral spreading and slope instability. The present work discusses the global dynamic response and interaction of an earth structure-foundation system, so as to determine quantitatively the collapse mechanism due to foundation's soil liquefaction. A levee-foundation system is simulated and the influence of characteristics of input ground motion, as well as, of the position of liquefied layer on the liquefaction-induced failure is evaluated. For the current levee model, its induced damage level (i.e. induced crest settlements) is strongly related to both liquefaction apparition and dissipation of excess pore water pressure on the foundation. The respective role of input ground motion characteristics is a key component for soil liquefaction apparition, as long duration of mainshock can lead to important nonlinearity and extended soil liquefaction. A circular collapse surface is generated inside the liquefied region and extends towards the crest in both sides of the levee. Even so, when the liquefied layer is situated in depth, no significant effect on the levee response is found. This research work provides a reference case study for seismic assessment of embankment-type structures subjected to earthquake and proposes a high-performance computational framework accessible to engineers.Keywords Dynamic analysis · Nonlinear coupled hydromechanical behavior · Soil liquefaction · Earthquake loading · strain localization · instability · FE modeling Liquefaction analysis and damage evaluation of embankment-type structures 3

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Section: Background Of Dynamic Liquefaction Analysismentioning

confidence: 99%

Liquefaction analysis and damage evaluation of embankment-type structures

Rapti

López-Caballero

Modaressi-Farahmand-Razavi

et al. 2018

Acta Geotech.

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“…Instability is triggered when the soil is loaded beyond the peak of the stress path (Kramer 1996). This peak also coincides with the vanishing of second-order work (Hill 1975); under the constraints of undrained loading, that is equivalent to the hardening modulus reaching a limiting value (Andrade 2009;Andrade et al 2013), as well as vanishing of the liquefaction matrix (Mohammadnejad and Andrade 2015). Once instability is triggered, the unstable soil loses strength and undergoes large deformations in a state of constant stress, termed the steady state (Fig.…”

Section: Mechanics Of Liquefaction Chartsmentioning

confidence: 69%

“…Liquefaction for a normally consolidated sand was numerically simulated in an undrained cyclic triaxial test using the Dafalias and Manzari (2004) plasticity model. Implementation details have been provided by Mohammadnejad and Andrade (2015). By successively varying the relative density of the numerical soil sample, a liquefaction chart was obtained for a normally consolidated sand as a function of relative density.…”

Section: Numerical Simulations Of Undrained Cyclic Triaxial Testmentioning

confidence: 99%

Flow Liquefaction Instability as a Mechanism for Lower End of Liquefaction Charts

Mital

Mohammadnejad

Andrade

2017

J. Geotech. Geoenviron. Eng.

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The state-of-the-practice uses the "simplified procedure" for evaluating liquefaction susceptibility of soils. Based on this procedure, liquefaction charts have been developed that correlate soil resistance to earthquake-induced stresses. These charts are based on case histories of past earthquakes and have proven to be useful while evaluating liquefaction susceptibility at a new site. However, these charts are inherently empirical, which makes extrapolation into regimes with insufficient data difficult. In addition, they do not inform an engineer about the effects of liquefaction. This work hypothesizes that the lower end of liquefaction charts corresponds to soils that are susceptible to unstable flow liquefaction. A numerical investigation is undertaken, the results of which support this hypothesis. This implies that if test data at a new site correspond to the lower end of liquefaction charts, then the site may be susceptible to flow liquefaction. This in turn could provide an engineer with some predictive power regarding the effects of liquefaction.

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“…Andrade [1], Andrade et al [2], and Mohammadnejad and Andrade [65] introduced a general mathematical criterion for flow liquefaction instability based on the seminal work of Borja [6,7] in which, the loss of equilibrium results in multiple feasible solutions that eventually results in instabilities. In multiaxial stress and strain spaces, Hill's loss of stability for infinite small deformations is [30]:…”

Section: Criterion For Flow Liquefaction Instabilitymentioning

confidence: 99%

“…(51) in Eq. (50) yields the general form for the criterion of flow liquefaction instability [1,2,65]:…”

Section: Criterion For Flow Liquefaction Instabilitymentioning

confidence: 99%

Prediction of flow liquefaction instability of clean and silty sands

Lashkari

2015

Acta Geotech.

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Adding a small amount of non-plastic silt to clean sands may lead to dramatic loss of shear strength and a noteworthy tendency toward contraction when the mechanical behavior of the mixture is compared with that of the clean host sand. Thus, simulation of the behavior of silty sands with varying fines content is still a challenging subject in geomechanics. A unified constitutive model for clean and silty sands is presented in this paper. To eliminate the factitious decrease of void ratio associated with inactive silt particles in various silty sand mixtures, the concept of equivalent void ratio is used in the model formulation instead of the global void ratio. In addition, the instantaneous soil state is expressed in terms of intergranular state parameter taking into account the combined influence of intergranular void ratio, mean principal effective stress and fines content. Then, dilatancy and plastic hardening modulus are directly linked to the intergranular state parameter. To improve the model capacity in simulation of cyclic tests, new features are added to the plastic hardening modulus. It is shown that the proposed model can reasonably reproduce the mechanical behavior as well as the onset of flow liquefaction instability of clean and silty sands using a unique set of parameters. List of symbolsA Dilatancy parameter (Eq. 22) B Model parameter (Eq. 31) b Fines participation factor (Eq. 2) c (=M e /M c ) Model parameter c h Plastic hardening parameter (Eq. 23) D pp , D pq , D qp , D qq See Eqs. (45)-(49) d Dilatancy function (Eq. 22) e Global void ratio e* Equivalent intergranular void ratio (Eq. 2) e 0

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Flow liquefaction instability prediction using finite elements

Cited by 21 publications

References 23 publications

Liquefaction analysis and damage evaluation of embankment-type structures

Liquefaction analysis and damage evaluation of embankment-type structures

Flow Liquefaction Instability as a Mechanism for Lower End of Liquefaction Charts

Prediction of flow liquefaction instability of clean and silty sands

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