Effect of Particle Shape on Constitutive Relation: DEM Study

Nguyen, Hoang Bao Khoi; Rahman, M.F.; Fourie, Andy

doi:10.1061/(asce)gt.1943-5606.0002278

Cited by 38 publications

(10 citation statements)

References 60 publications

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“…The CS data from the undrained simulations in this study and previous studies for the same granular materials formed a unique CSL in the q-p and e-log(p ) spaces (see Figure 4) [67,68]. The CSL or M line in Figure 4a has a slope of approximately 0.9.…”

Section: Critical State Soil Mechanics Framework In Demsupporting

confidence: 61%

An Investigation of Instability on Constant Shear Drained (CSD) Path under the CSSM Framework: A DEM Study

2022

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Soil liquefaction or instability, one of the most catastrophic phenomena, has attracted significant research attention in recent years. The main cause of soil liquefaction or instability is the reduction in the effective stress in the soil due to the build-up of pore water pressure. Such a phenomenon has often been thought to be related to the undrained shearing of saturated or nearly saturated sandy soils. Notwithstanding, many researchers also reported soil instability under a drained condition due to the reduction in lateral stress. This condition is often referred to as the constant shear drained (CSD) condition, and it is not uncommon in nature, especially in a soil slope. Even though several catastrophic dam failures have been attributed to CSD failure, the failure mechanisms in CSD conditions are not well understood, e.g., how the volumetric strain or effective stress changes at the triggering of flow deformation. Researchers often consider the soil fabric to be one of the contributors to soil behaviour and use this parameter to explain the failure mechanism of soil. However, the soil fabric is difficult to measure in conventional laboratory tests. Due to that reason, a numerical approach capable of capturing the soil fabric, the discrete element method (DEM), is used to investigate the CSD shearing mechanism. A series of simulations on 3D assemblies of ellipsoid particles was conducted. The DEM specimens exhibited instability behaviour when the effective stress paths nearly reached the critical state line. It can be clearly observed that the axial and volumetric strains changed suddenly when the stress states were close to the critical state line. Alongside these micromechanical observations, the study also presents deeper insights into soil behaviour by relating the macro-observations to the micromechanical aspect of the soil.

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Section: Critical State Soil Mechanics Framework In Demsupporting

confidence: 61%

An Investigation of Instability on Constant Shear Drained (CSD) Path under the CSSM Framework: A DEM Study

2022

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“…Note that the future reference critical state is a state which can be reached by soils subjected to sufficient shearing. This state was experimentally and numerically evidenced in many reported researches [ 3 , 4 , 6 , 7 , 26 , 27 , 28 ], and characterized by the critical state lines in the mean effective stress v.s. deviator stress space and the mean effective stress v.s.…”

Section: Progress In Fpmentioning

confidence: 66%

“…However, there is one other option: that is to use the stress ratio at the phase transformation state, i.e.,

, to determine the fractional order as suggested by Liang, et al [ 40 ]. As suggested by Nguyen and his coworkers [ 26 , 27 , 28 , 36 , 37 ], the phase-transformation-state parameter (

) and strain hardening parameter (

) are also a function of M and the state parameter.…”

Section: Progress In Fpmentioning

confidence: 99%

“…Specifically speaking, to capture the stress-dilatancy behaviour of granular soil, the following fractional-order dilatancy ratio (

) based on the Modified Cam-clay (MCC) function was proposed [ 33 ]:

where

and

, are the mean effective stress and deviatoric stress, respectively;

is the Kronecker delta; M and

denote the critical-state and current-state stress ratios, respectively. Unlike other critical state parameters, the critical-state stress ratio (M) can be influenced by many factors, e.g., the particle shape [ 27 ], but it should not be affected by fines content [ 26 , 36 ] or shearing mode [ 28 , 37 ]. The effect of

on the stress-dilatancy behaviour of granular soil can be observed in Figure 2 .…”

Section: Progress In Fpmentioning

confidence: 99%

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Review on Stress-Fractional Plasticity Models

Sun

Sumelka

2022

Materials

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Fractional calculus plays an increasingly important role in mechanics research. This review investigates the progress of an interdisciplinary approach, fractional plasticity (FP), based on fractional derivative and classic plasticity since FP was proposed as an efficient alternative to modelling state-dependent nonassociativity without an additional plastic potential function. Firstly, the stress length scale (SLS) is defined to conduct fractional differential, which influences the direction and intensity of the nonassociated flow of geomaterials owing to the integral definition of the fractional operator. Based on the role of SLS, two branches of FP, respectively considering the past stress and future reference critical state can be developed. Merits and demerits of these approaches are then discussed, which leads to the definition of the third branch of FP, by considering the influences of both past and future stress states. In addition, some specific cases and potential applications of the third branch can be realised when specific SLS are adopted.

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“…Similar to the results for undrained behaviour, q peak increases exponentially with C C as shown in Figure 10a with an R 2 value of 0.99. The dilatancy (d), which is defined as the rate of plastic volume change (dε p v ) with the plastic deviatoric strain (dε p q ), is an important characteristic behaviour of drained soil [114][115][116] and has been used in prediction/constitutive modelling of soil behaviour [117,118]. The dilatancy (d) can be calculated using Equation (8).…”

Section: Drained Behaviourmentioning

confidence: 99%

State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications

et al. 2020

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Microbial-induced calcite precipitation (MICP) is a promising new technology in the area of Civil Engineering with potential to become a cost-effective, environmentally friendly and sustainable solution to many problems such as ground improvement, liquefaction remediation, enhancing properties of concrete and so forth. This paper reviews the research and developments over the past 25 years since the first reported application of MICP in 1995. Historical developments in the area, the biological processes involved, the behaviour of improved soils, developments in modelling the behaviour of treated soil and the challenges associated are discussed with a focus on the geotechnical aspects of the problem. The paper also presents an assessment of cost and environmental benefits tied with three application scenarios in pavement construction. It is understood for some applications that at this stage, MICP may not be a cost-effective or even environmentally friendly solution; however, following the latest developments, MICP has the potential to become one.

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Effect of Particle Shape on Constitutive Relation: DEM Study

Cited by 38 publications

References 60 publications

An Investigation of Instability on Constant Shear Drained (CSD) Path under the CSSM Framework: A DEM Study

An Investigation of Instability on Constant Shear Drained (CSD) Path under the CSSM Framework: A DEM Study

Review on Stress-Fractional Plasticity Models

State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications

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