Multi-scale mechanics of sand based on FEM-DEM coupling method

Zhou, Qian; Xu, Wenjie; Lubbe, Retief

doi:10.1016/j.powtec.2020.11.006

Cited by 25 publications

(12 citation statements)

References 21 publications

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“…The ME is located inside the shear band at this size and shows relatively smooth behaviour. This size agrees well with the literature where DEM is combined in multi‐scale modelling 53,54 …”

Section: Selection Of Mesoscale Representative Volume Elementsupporting

confidence: 91%

Strain localization in the standard triaxial tests of granular materials: Insights into meso‐ and macro‐scale behaviours

Phan,

Bui,

Nguyen

et al. 2024

Num Anal Meth Geomechanics

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The standard triaxial tests cease to be valid as material tests since the homogeneity of the granular mass is lost when localized failures such as shear bands occur requiring a different approach to interpreting and analyzing material responses at the meso scale from the macro behaviour. This study sheds light on the above issue by analyzing the standard triaxial tests of the granular specimens undergoing localized failure at different scales using DEM. For the first time, the behaviour of material inside and outside of the shear band as well as the entire sample are quantitatively quantified through DEM simulations. The results enable confirmation of various theoretical hypotheses and experimental observations on the localized failure in granular materials. For example, by quantifying the inter‐particle contact forces of materials inside and outside the shear band zone, it is confirmed that the material outside the localization band undergoes inelastic unloading beyond the bifurcation point, while those inside the localization band experience inelastic shearing to reach the critical state. Moreover, the analysis in this study suggests that if the volume of the localization zone can be precisely measured from the experiment, the mesoscale constitutive responses that truly represent the inelastic behaviour can be quantified. This gives rise to a more appropriate method to obtain inelastic constitutive responses of granular materials from specimens undergoing localized failure in triaxial tests.

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Section: Selection Of Mesoscale Representative Volume Elementsupporting

confidence: 91%

Strain localization in the standard triaxial tests of granular materials: Insights into meso‐ and macro‐scale behaviours

Phan,

Bui,

Nguyen

et al. 2024

Num Anal Meth Geomechanics

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“…Itasca provides Socket I/O connections functions to enable the coupling of PFC and FLAC, through which the two codes are able to exchange data at each time step (Qian et al 2013). The PFC and FLAC coupling method has been widely applied in various elds of geotechnical engineering Feng et al 2021;Zhou et al 2021). Therefore, the PFC and FLAC coupling method is suitable for simulating landslide deformation and failure processes containing weak interlayers.…”

Section: Methodsmentioning

confidence: 99%

Numerical simulation study on the deformation and failure of a gently inclined bedding slope: a case study of the Jinhaihu landslide in Guizhou, China

Liu

Shi

Peng

et al. 2022

Preprint

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At approximately 7:00 p.m. on January 3, 2022, a bedding landslide (referred to as the Jinhaihu landslide in this paper) occurred in the Jinhaihu District of Bijie city, Guizhou Province, China, resulting in the death of 14 laborers. The catastrophic landslides induced by the geological conditions in the study area are incomprehensible and deserve an in-depth study of their genetic mechanisms. In this paper, a detailed field investigation was conducted on the Jinhaihu landslide, and the geological background of the landslide area and the characteristics of the landslide were well revealed. The slide zone and rock samples of the landslide site were obtained for physical and mechanical tests to further establish a coupled PFC/FLAC2D model of the landslide area and analyze the genetic mechanism of the Jinhaihu landslide using numerical simulation. The results indicate that the landslide area has been disturbed by long-term engineering, and a large amount of excavation at the foot of the slope has reduced the resistance of the landslide to slide downward, increased the damage to the slope, and provided space for the landslide to move. However, the excavation did not immediately initiate the landslide at the toe, and the claystone containing a large number of illite clay minerals (56.5%) gradually weakened with the infiltration of rainfall before the slope finally failed. The numerical simulation indicated that the excavation at the toe of the slope caused cracks at the crown, the softening of the claystone caused the sliding mass to be divided into blocks by the cracks, and then the sliding mass slid downward along the weak interlayer. First, the sliding mass toppled down and disintegrated at the front edge, and the rear of the sliding mass was tensile-fractured and failed. The movement of the rock blocks on the slide bed has the character of translation with almost no rotation. The evolution process of landslides is divided into four stages: the initial stage, fracture generation stage, softening stage and overall failure stage. The research results of this paper provide a reference for the risk evaluation and disaster prevention of the same category of landslides.

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“…Much progress has been made in the FEM×DEM modelling in recent years, in both methodology enhancement and mechanical investigation of granular material/structure: proposing higher‐order model and mesh dependency regularization, 17,35,36 3D macro‐micro model development 17,37–39 ; studying the model performance and advanced computing scheme 17,19,39,40 ; investigating the anisotropy origin/behaviour 41–43 ; and application to engineering problems 41,44–46 . However, regarding the particle interaction, most of these later works considered the particles interactions as purely frictional or simple cohesive‐frictional law and ignored rolling resistance effect and/or rolling resistance strength, which is not accurately appropriated for CGM.…”

Section: Introductionmentioning

confidence: 99%

FEM×DEM multi‐scale model for cemented granular materials: Inter‐ and intra‐granular cracking induced strain localisation

Nguyen

Desrues

et al. 2022

Num Anal Meth Geomechanics

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In this paper, we present a multi‐scale model that combines the finite element method (FEM) and the discrete element method (DEM) to study the behaviour of cemented granular materials (CGM) at both the sample (macroscopic) and particle (microscopic) scales, taking into account inter‐ and intra‐granular cracking. At the microscopic scale, the material is made up of Volume Elements (VE) composed of particles. Their mechanical behaviour is modelled by the DEM. In the VEs, we find circular grains (single particles) and meso‐grains; the meso‐grains being made up of clusters of particles linked by strong cohesive bonds. All particles interact via normal/tangential contact and rolling resistance laws with cohesive bonds. At the macroscopic scale, the sample is modelled using the FEM. A VE is assigned to each Gauss point of the mesh; the mechanical response of the VE is used to numerically derive the constitutive response of the material to the strain increment exerted at each point. In the models reported in this paper, localised failures in shear band mode are observed at the macroscopic scale. By performing a microscopic analysis, the results show that the occurrence and development of shear bands give rise locally to a strong evolution of microscopic characteristics such as void ratio, number of contacts (total and debonding contacts), and remarkably by inter‐ and intra‐granular cracking in the case of meso‐grains. Furthermore, the stress and strain tensors non‐coaxiality is clearly demonstrated inside the shear band, but almost negligible outside.

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Multi-scale mechanics of sand based on FEM-DEM coupling method

Cited by 25 publications

References 21 publications

Strain localization in the standard triaxial tests of granular materials: Insights into meso‐ and macro‐scale behaviours

Strain localization in the standard triaxial tests of granular materials: Insights into meso‐ and macro‐scale behaviours

Numerical simulation study on the deformation and failure of a gently inclined bedding slope: a case study of the Jinhaihu landslide in Guizhou, China

FEM×DEM multi‐scale model for cemented granular materials: Inter‐ and intra‐granular cracking induced strain localisation

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