DEM simulation of the pullout behavior of geogrid-stabilized ballast with the optimization of the coordination between aperture size and particle diameter

Miao, Chenxi; Jia, Yafei; Zhang, Jun; Jin, Zhen

doi:10.1016/j.conbuildmat.2020.119359

Cited by 17 publications

(8 citation statements)

References 37 publications

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“…In order to obtain quantitatively reliable mechanical behavior, these geogrid models need to be calibrated. In previous DEM studies [ [14][15][16][17][18], the determination of the values of these parameters was a complex task, considering the stiffness and the friction coefficient f of the spheres constituting the geogrid. Moreover, the parameters of the bonds control the flexibility and strength of the geogrid, and their adjustment requires different experiments, in which each parameter or group of parameters acts independently.…”

Section: Calibration Of Fdm Geogrid Modelmentioning

confidence: 99%

“…In contrast with the above continuous element methods, the discrete element method has been frequently used to study the interaction between geogrids and soil [13][14][15][16]. The geogrid has been modeled using a set of bonded particles to form the geogrid's true shape and the surrounding soil particles have been modeled using clumps or balls.…”

Section: Introductionmentioning

confidence: 99%

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DEM-FDM Coupled Numerical Study on the Reinforcement of Biaxial and Triaxial Geogrid Using Pullout Test

Jianjun

Chen

et al. 2021

Applied Sciences

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The key to modeling the interlocking of geogrid-reinforced ballast is considering both the continuous deformation characteristics of the geogrid and the discontinuity of the ballast particles. For this purpose, pullout tests using biaxial and triaxial geogrids were simulated using the coupled discrete element method (DEM) and finite difference method (FDM). In this coupled model, two real-shaped geogrid models with square and triangular apertures were established using the solid element in FLAC3D. Meanwhile, simplified shaped clumps were used to represent the ballast using PFC3D. The calibration test simulation showed that the accurately formed geogrid model can reproduce the deformation and strength characteristics of a geogrid. The pullout simulation results show that the DEM-FDM method can well predict the relationship between pullout force and displacement, which is more accurate than the DEM method. For ballast particles of 40 mm in size, both the experiment and simulation results showed that the triaxial geogrid of 75 mm is better than the 65-mm biaxial geogrid . In addition, the DEM-FDM method can study the interaction mechanism between the particles and the geogrid from a microscopic view, and also reveal the similar deformation behavior of the geogrid in the pullout process. Therefore, the DEM-FDM coupled method can not only investigate the interlocking mechanism between the ballast and particles but can also provide a great method for evaluating the performance of different types of geogrids.

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Section: Calibration Of Fdm Geogrid Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DEM-FDM Coupled Numerical Study on the Reinforcement of Biaxial and Triaxial Geogrid Using Pullout Test

Jianjun

Chen

et al. 2021

Applied Sciences

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“…Qian et al [31] carried out the triaxial test of ballast material reinforced by triangular and square aperture geogrids. Miao et al [10] carried out the pull-out test of geogrid-stabilized ballast based on the discrete element method. Chen et al [11] proposed a discrete element model for cyclic loads of geogrid-reinforced ballast under confined and unconfined conditions.…”

Section: Shear Stress-displacement Analysismentioning

confidence: 99%

“…As an effective numerical approach, the discrete element method has been used to analyze the geogrid-reinforced ballast behaviors [8,9]. Miao et al [10] presented the pull-out behavior of a triangular geogrid embedded in ballast under special consideration of the particle size using the discrete element method.…”

Section: Introductionmentioning

confidence: 99%

A Coupled Discrete-Finite Element Method for Shear Strength Analysis of Geogrid-Reinforced Railway Ballast

Jun-jie

et al. 2021

Advances in Materials Science and Engineering

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This paper presents a coupled discrete-finite element method for the investigation of shear strength of geogrid-reinforced ballast by direct shear tests and pull-out tests. The discrete element method (DEM) and finite element method (FEM) are employed to simulate ballast and geogrid, respectively. Irregularly shaped ballast particles are modeled with clumps, and the nonlinear contact force model is used to calculate contact force between particles. Continuum geogrid is modeled by a two-node beam element with six degrees of freedom. A contact algorithm based on the static equilibrium is proposed at the geogrid-ballast contact surface. The simulation results indicate that shear strengths increase with the installation of geogrid. Moreover, ballast particle displacements and nominal volumetric strains are analyzed to provide a microscopic view on the mechanism of the reinforcement effect of geogrid.

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“…Li et al [8] developed a series of geogrid-reinforced ballast models with different geogrid sizes and particular structures to reproduce the mechanical behavior of the geogrid under pull-out load and the rationality of the DEM model is verified by comparing the evolution law pull-out force measured by laboratory tests and numerical simulations under comparable conditions. Miao et al [9] presented the pull-out behavior of a triangular geogrid embedded in a ballast under special consideration of the particle size based on the well-established constitutive models and particular configurations used in the discrete element method (DEM) simulation of the geogrid-stabilized ballast system.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and Mesoscopic Characteristics of Indirectly Reinforced Gravelly Soil by a Geogrid

Liu¹,

Wang²,

Sun³

2022

Advances in Materials Science and Engineering

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The geogrid is a type of spatial network structure with a certain thickness; through its interactions with the surrounding soil, the soil can be reinforced. In this study, the characteristics of the interface between the geogrid and gravelly soil were investigated with a pull-out test. To investigate the mesoscopic characteristics of the geogrid-soil interface, the Particle Flow Code 3D (PFC3D) program was employed to simulate the pull-out test, which can reproduce the evolution of the influencing zones of the geogrid during the pull-out test from macroscopic and mesoscopic perspectives. Both sides of the geogrid were characterised by a shear zone and an advanced influencing zone. The geogrid indirectly reinforced the soil within the influencing zones to a certain extent, and the thickness of this zone was rarely related to the normal pressure. Additionally, the widths of the influencing zones above and below the interface were different; the above one was wider.

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DEM simulation of the pullout behavior of geogrid-stabilized ballast with the optimization of the coordination between aperture size and particle diameter

Cited by 17 publications

References 37 publications

DEM-FDM Coupled Numerical Study on the Reinforcement of Biaxial and Triaxial Geogrid Using Pullout Test

DEM-FDM Coupled Numerical Study on the Reinforcement of Biaxial and Triaxial Geogrid Using Pullout Test

A Coupled Discrete-Finite Element Method for Shear Strength Analysis of Geogrid-Reinforced Railway Ballast

Mechanism and Mesoscopic Characteristics of Indirectly Reinforced Gravelly Soil by a Geogrid

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