Three dimensional discrete element modeling of granular media under cyclic constant volume loading: A micromechanical perspective

Soroush, Abbas; Ferdowsi, Behrooz

doi:10.1016/j.powtec.2011.04.007

Cited by 46 publications

(17 citation statements)

References 22 publications

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“…(19) and (20) The newly introduced d c is used to describe the effect of cyclic loading history on sand dilatancy. It is commonly observed that, during undrained cyclic loading with moderate stress ratio, the rate of excess pore water pressure increases dramatically at the onset of loading direction reversal when the stress state goes above the phase transformation line, which may be attributable to the fact that the highly anisotropic void space system that has developed due to fabric evolution can be extremely unstable when the loading direction changes (Oda et al 2001;Sazzad and Suzuki 2010;Soroush and Ferdowsi 2011 (20) is essential for getting a better fit of sand behavior in cyclic loading but has its own drawback as one cannot distinguish whether the plastic volumetric strain is caused by the shear or compression mechanism. Indeed, other similar approaches have also been proposed to model the cyclic loading history on sand behavior by employing plastic deformation-dependent dilatancy relation and/or plastic modulus (e.g., Wang et al 1990;Oka et al 1999;Li 2002;Ling and Yang 2006;Wang and Xie 2014).…”

Section: Plastic Modulus and Dilatancy Relation For Constant Mean Strmentioning

confidence: 99%

Constitutive Modeling of Anisotropic Sand Behavior in Monotonic and Cyclic Loading

Gao

Zhao

2015

J. Eng. Mech.

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An anisotropic plasticity model is proposed to describe the fabric effect on sand behavior under both monotonic and cyclic loading conditions within the framework of anisotropic critical state theory. The model employs a cone-shaped bounding surface in the deviatoric stress space and a yield cap perpendicular to the mean stress axis to describe sand behavior in constant mean stress shear and constant stress ratio compression, respectively. The model considers a fabric tensor characterizing the internal structure of sand associated with the void space system and its evolution with plastic deformation. The fabric evolution law is assumed to render the fabric tensor to become codirectional with the loading direction tensor and to reach a constant magnitude of unit at the critical state. In constant stress ratio compression, the final degree of anisotropy is proportional to a normalized stress ratio. An anisotropic variable defined by a joint invariant of the fabric tensor and loading direction tensor is employed to describe the fabric effect on sand behavior in constant mean stress monotonic and cyclic shear. A systematic calibrating procedure of the model parameters is presented. Satisfactory comparison is found between the model simulations and test results on Toyoura sand in both monotonic and cyclic loadings with a single set of parameters. The important role of fabric and fabric evolution in capturing the sand behavior is highlighted. Limitations and potential improvement of the model in describing cyclic mobility of very dense sand and sand behavior in nonproportional loading have been discussed.

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Section: Plastic Modulus and Dilatancy Relation For Constant Mean Strmentioning

confidence: 99%

Constitutive Modeling of Anisotropic Sand Behavior in Monotonic and Cyclic Loading

Gao

Zhao

2015

J. Eng. Mech.

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“…If 'weak' restraint is lost, rearrangement and large straining can occur in a buckling-like manner (Nicot and Darve 2010). Soroush and Ferdowsi (2011) found DEM contact forces become more anisotropic with each cycle of strain-controlled loading ( Figure 5) and Thornton (2000) states DEM-simulated shear deformation causes separation of particle contacts orthogonal to the deviator stress. A similarly increasing anisotropy is p. 12 found with simulation of stress-controlled cyclic loading by Xu et al (2015).…”

Section: Undrained Cyclic Failure In the Critical State Modelmentioning

confidence: 93%

Degradation of soft subgrade soil from slow, large, cyclic heavy-haul road loads: a review

et al. 2016

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Extraction of resources in remote locations can require temporary haul roads to transport extremely large, slow-moving, indivisible loads (e.g., plant, oil–gas production modules, and reactors, weighing in excess of 1000 t) without interruptions. Poor subgrade soils may experience larger cyclic strains and greater cyclic degradation under these conditions than under conventional roads, yet the short engineering life precludes many foundation-strengthening options due to cost. As there is little research into this unique situation, this paper synthesizes research from a broad range of applications to discuss implications on expected soil response. Reference is made to critical state theory and discrete element method (DEM) modelling to develop fundamental concepts considering particle-scale interactions. Cyclic failure is proposed to be a kinematically unstable process, triggered by shear banding on the Hvorslev surface, tensile liquefaction or fabric-governed meta-stable liquefaction; the latter is particularly influenced by stress history and anisotropy. This paper finds pore-water pressure accumulation under load and dissipation between loads are key to cyclic degradation and furthermore to be dependent upon load duration, principal stress rotation, and repetition frequency. For meta-stable, liquefiable soils in particular, inclination of principal stresses is at least as important in assessing failure risk as magnitude of stresses.

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“…Their results qualitatively agreed with physical tests on sand. Recently, although there have been a number of both 2D (Sitharam, 2003) and 3D (O'Sullivan et al, 2008;Sitharam et al, 2009;Soroush & Ferdowsi, 2011) numerical simulations that have investigated liquefaction phenomenon based on strain-controlled loading, the authors are not aware of any DEM studies that have explored the micromechanics both of liquefaction and of CRR in a stress-controlled manner, and further developed a CRR-V s1 correlation by microscopically measuring the V s of granular soils.…”

Section: Introductionmentioning

confidence: 99%

Correlation between liquefaction resistance and shear wave velocity of granular soils: a micromechanical perspective

Xu¹,

LING²,

Cheng³

et al. 2015

Géotechnique

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The shear wave velocity method has become an increasingly popular means to evaluate the liquefaction potential of granular soils. Understanding the fundamental mechanism underlying existing empirical or semi-empirical relationships is important for better assessing their reliability. This paper presents a particle-scale study of the correlation between cyclic resistance ratio (CRR) and the shear wave velocity corrected for overburden stress (V s1). The discrete-element method was used to simulate a series of undrained stress-controlled cyclic triaxial tests together with shear wave velocity (V s) measurements. Discrete-element method modelling with various relative densities, confining pressures and micro-parameters was performed under various cyclic stress ratios (CSRs), and the onset of liquefaction was illustrated through both macroscopic and microscopic responses, for example, inferred excess pore-water pressure, mechanical coordination number and redundancy index. The inter-particle friction was identified as the key micro-parameter that governs the liquefaction resistance of granular soils. A micro-scale CRR-V s1 correlation considering two independent micro-parameters, inter-particle friction and particle shear modulus, was then obtained and further validated with the outcomes from three dynamic centrifuge model tests performed on silica sand no. 8. This study demonstrates that the CRR-V s1 correlation is particle specific, thus soil specific, and the particle mechanical properties should be included in the V s-based method for future liquefaction evaluation of granular soils.

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Three dimensional discrete element modeling of granular media under cyclic constant volume loading: A micromechanical perspective

Cited by 46 publications

References 22 publications

Constitutive Modeling of Anisotropic Sand Behavior in Monotonic and Cyclic Loading

Constitutive Modeling of Anisotropic Sand Behavior in Monotonic and Cyclic Loading

Degradation of soft subgrade soil from slow, large, cyclic heavy-haul road loads: a review

Correlation between liquefaction resistance and shear wave velocity of granular soils: a micromechanical perspective

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