Upscaling critical state considering the distribution of meso‐structures in granular materials

Wang, Xiaoxiao; Liu, Yang; Yu, Pengqiang

doi:10.1002/nag.3217

Cited by 6 publications

(6 citation statements)

References 50 publications

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“…In this section, additional numerical simulations with four cases of friction coefficient µ ( µ = 0.1, 0.5, 0.75 and 0.9) are carried out but adopting the same modeling parameters with the case of µ = 0.25. As shown in Figure 18A, the shear strength and volumetric strain increases with increasing µ but becomes less sensitive to µ when µ > 0.5, which agrees with the results of some investigations 48,56–58 . In addition, the macro stress‐dilatancy relations are nonlinear in Figure 18B, and the stress level corresponding to the zero dilatancy increases with the increase of µ .…”

Section: The Micro‐mechanism Of Stress‐dilatancy Anisotropysupporting

confidence: 87%

“…It suggests that the changes of contact distribution are closely related to the stress-dilatancy relationship of granular materials. For the most current studies, [46][47][48][49] Discrete Element Method (DEM) is wildly used to investigate the micromechanism of macroscopic behaviors of granular materials which provides abundant information of micromechanics and microstructures. In this sense, following the affine and nonaffine components of microcontact displacement, the anisotropic stress-dilatancy relation is meaningful to be investigated using DEM.…”

Section: Introductionmentioning

confidence: 99%

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Micro‐mechanism of stress‐dilatancy anisotropy in granular materials: Affine and nonaffine deformation

Liu,

Wang

2024

Num Anal Meth Geomechanics

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The stress‐induced dilatancy anisotropy is an important kinematic response in granular materials and is very complex due to the stochastic motion of particles. In this study, the local stress‐dilatancy relationship is investigated referring to the local contact force and relative displacement in a certain contact direction. The micromechanism of this anisotropy is investigated from the view of affine and nonaffine approaches based on DEM simulation. Numerical results indicate that the local nonaffine dilatancy/contraction tendency is opposite with that of local affine deformation in macroscopic compression and extension direction, which mainly stems from the counteraction effect between the normal components of affine and nonaffine displacements. The local stress‐dilatancy of affine and nonaffine components is linear and orientation‐dependent, which results in the nonlinear character of macroscopic stress‐dilatancy. By establishing an analytical relation of stress‐dilatancy, the local affine/nonaffine dilatancy is decomposed into the component of stress‐induced dilatancy synchronized with the local stress anisotropy; and the component of stress‐induced dilatancy asynchronized with the local stress anisotropy. The former is related to the unchanged isotropic microstructure, and the latter attributes to the anisotropic microstructure. Besides, the contribution of nonsliding contacts to nonaffine dilatancy is larger than that of sliding contacts even for the case of relatively higher sliding ratio, which indicates that the heterogeneous deformation attributes not only to the friction dissipation, but to the blocked energy at micro contacts in granular materials.

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Section: The Micro‐mechanism Of Stress‐dilatancy Anisotropysupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Micro‐mechanism of stress‐dilatancy anisotropy in granular materials: Affine and nonaffine deformation

Liu,

Wang

2024

Num Anal Meth Geomechanics

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“…e discrete element method has significant advantages in simulating cracks and large deformations. It only needs to consider the contact properties between particles and does not need to define the overall complex constitutive relationship [38][39][40]. e instability model of rock slopes containing joints under gravity is simulated in PFC 6.0 by synthetic rock mass, as shown in Figure 1.…”

Section: Microfracture and Joint Surface In Rockmentioning

confidence: 99%

Stability Analysis of Jointed Rock Cutting Slope Based on Discrete Element Method

Zhu

Gao

Zhao

et al. 2022

Advances in Civil Engineering

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The joints in the rock mass are essential for the stability of rocky slopes, and the destabilization damage of the slope is often directly related to the joints. In this study, in order to reveal the instability process and mechanism of rock slopes from a microscale perspective, the DEM simulations for rocky slopes of the K88 + 400∼K88 + 540 section of Zhongkai Expressway are carried out considering the influence of joints. Based on the findings of the on-site jointed structural surfaces, a rocky slope model containing two sets of intermittent joints was constructed, and the linear parallel bond model and the smooth joint model are used to characterize the rock body and joints, respectively. The evolution of microfracture, contact force chain, and particle displacement are analyzed to explore the micromechanism of slope instability. Finally, the triple reinforcement scheme of anchor cable frame and grass planting is proposed. The research results can provide a reference for stability analysis and reinforcement of similar rocky slope projects.

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“…Generally, there are two classes of method used in modeling the mechanical behaviors of granular media, called discrete element method and equivalent continuum method. In recent years, due to the rapid development of computer technology and numerical software, many breakthroughs have been achieved in understanding the static and dynamic properties of granular materials from a microscale viewpoint based on the discrete element method [10][11][12]. On the other hand, the continuous method is always a convenient and effective method to describe the mechanical properties of materials [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Propagation Characteristics of Rotation Waves in Transversely Isotropic Granular Media Considering Microstructure Effect

Liu

Shi

et al. 2022

Applied Sciences

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The purpose of this study is to develop a micromechanical-based microstructure model for transversely isotropic granular media and then use it to investigate the propagation characteristics of particle rotation waves. In this paper, the particle translation and rotation are selected as basic independent variables and the particle displacement at contact due to particle rotation is ignored. The relative deformation tensors are introduced to describe the local deformational fluctuation because of their discrete nature and microstructure effect. Based on micro–macro deformation energy conservation, the constitutive relations are derived through transferring the summation into an integral and introducing the contact fabric tensor. The governing equations and corresponding boundary conditions can then be obtained based on Hamilton’s principle. Subsequently, the dispersion characteristics and bandgap features of particle rotation waves in transversely isotropic granular media are analyzed based on the present model. The research shows that: the present microstructure model can predict 12 particle rotation waves and reflect 8 dispersion relations; the effect of the change in fabric on the dispersion relation of particle rotation waves can be mainly attributed to the effect of equivalent stiffness on frequency; and the degree of anisotropy has significant effects on the width of frequency bandgap of longitudinal waves, while it has little effect on the width of frequency bandgap of transverse and in-plane shear waves.

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Upscaling critical state considering the distribution of meso‐structures in granular materials

Cited by 6 publications

References 50 publications

Micro‐mechanism of stress‐dilatancy anisotropy in granular materials: Affine and nonaffine deformation

Micro‐mechanism of stress‐dilatancy anisotropy in granular materials: Affine and nonaffine deformation

Stability Analysis of Jointed Rock Cutting Slope Based on Discrete Element Method

Propagation Characteristics of Rotation Waves in Transversely Isotropic Granular Media Considering Microstructure Effect

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