Discrete element modelling of lateral displacement of a granular assembly under cyclic loading

Chen, Cheng; Indraratna, Buddhima; McDowell, G. R.; Rujikiatkamjorn, Cholachat

doi:10.1016/j.compgeo.2015.06.006

Cited by 66 publications

(54 citation statements)

References 19 publications

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“…Although box test simulates a small portion of railway track, it needs a non-traditional large-scale equipment to be designed and developed. There are two main materials used to build the box; wood [89,90,92] and steel [93][94][95][96][97][98]. Some researchers [91,99,100] used other transparent material like Perspex sheet to be used in one side of the steel box for better observation to the test sample during testing.…”

Section: Large Scale Equipmentmentioning

confidence: 99%

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Large-scale triaxial and box testing on railroad ballast: a review

Alabbasi

Hussein

2019

SN Appl. Sci.

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The use of railway transportation systems has been increased throughout the years. The conventional ballasted tracks have been used widely in many countries around the world. Ballast material is the basic element of ballasted tracks. Ballast degrades and deforms after service. Therefore, periodical ballast maintenance is needed which is a cost and time expensive activity. Understanding ballast mechanical behavior leads to better design and efficient maintenance. From the literature, experimental approach is used to understand the mechanical behavior of railroad ballast. Traditional experimental tests provide inaccurate results due to the large ballast particle size with relative to sample size. Researchers used large scale triaxial and box tests extensively to understand the mechanical behavior of railroad ballast. The target of this paper is to present a concise review of the extensive literature presented on the mechanical behavior of railroad ballast using large scale triaxial and box testing. It discusses the various aspects of large-scale equipment such as apparatus' setup , size, material and shape, simulated load condition and test purpose. It presents the key findings of the large-scale triaxial and box tests in understanding ballast mechanical behavior.

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Section: Large Scale Equipmentmentioning

confidence: 99%

“…18. Other studies [96,97] used this apparatus to study the influence of geogrid reinforcement on ballast lateral settlement. The authors showed the significance of using geogrid in reducing ballast lateral settlement.…”

Section: Main Findings Of Understanding Ballast Behavior Using Box Testmentioning

confidence: 99%

Large-scale triaxial and box testing on railroad ballast: a review

Alabbasi

Hussein

2019

SN Appl. Sci.

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“…Independent from the particle type chosen, most citations mentioned above used rather complex shapes to model in high detail the complex shape of railway ballast stones. Exceptions, like [6,7,24] who use simple shape models, only obtained qualitative not quantitative agreement between simulations and experiments. The usage of simple particle shapes for quantitative comparison with experiments is a continuation of the authors' previous works.…”

Section: Introductionmentioning

confidence: 96%

“…The constructed clumps are detailed shape models, which usually results in a high number of spheres (above 10 in [17] and above 50 in [11]). In contrast to this, [6] investigated the usage of geometric clumps (tetrahedral or flaky) consisting of up to eight spheres. In [24], results of simulation with complex particle shapes were compared to those using a simple two ball clump and qualitatively similar results were obtained.…”

Section: Introductionmentioning

confidence: 99%

Simple particle shapes for DEM simulations of railway ballast: influence of shape descriptors on packing behaviour

Suhr

Six

2020

Granular Matter

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In any DEM simulation, the chosen particle shape will greatly influence the simulated material behaviour. For a specific material, e.g. railway ballast, it remains an open question how to model the particle shape, such that DEM simulations are computationally efficient and simulation results are in good accordance with measurements. While DEM shape modelling for railway ballast is well addressed in the literature, approaches mainly aim at approximating the stones' actual shape, resulting in rather complex and thus inefficient particle shapes. In contrast, very simple DEM shapes will be constructed, clumps of three spheres, which aim to approximate shape descriptors of the considered ballast material. In DEM simulations of the packing behaviour, a set of clump shapes is identified, which can pack at porosities observed at track sites, as well as in lab tests. The relation between particle shape (descriptors) and obtained packing (characteristic) is investigated in a correlation analysis. The simulated packing's porosity is strongly correlated to four shape descriptors, which are also strongly correlated among each other. Thus, to derive simple shape models of a given particle shape, matching one of these shape descriptors, might be a good first step to bring simulated porosities closer to measured ones. The conducted correlation analysis also shows that packing's coordination number and isotropic fabric are correlated to more shape descriptors, making it more difficult to estimate the effect of particle shape on these quantities.

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“…Reducing ballast degradation is necessary for solving safety and economic problems [15,16]. More importantly, a new problem has occurred in some areas where the lack of high-quality parent rock has The main methodology applied in this study is numerical simulation with DEM models, since the DEM has been a viable tool for railway ballast simulation and successfully applied in many studies, e.g., [1,15,[28][29][30][31][32][33][34][35][36][37]. Because railway ballast is one kind of granular material, continuum models such as the finite element method or finite difference method are not able to present realistic ballast characteristics (e.g., movements, morphology and degradation).…”

Section: Introductionmentioning

confidence: 99%

Discrete Element Modelling of Rubber-Protected Ballast Performance Subjected to Direct Shear Test and Cyclic Loading

Guo

Zhou

et al. 2020

Sustainability

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The rubber-protected ballast (RPB) is made from natural ballast particles and crumb rubber particles. The crumb rubber is shredded waste tires. RPB was chosen to replace the ballast as it has higher resistance to breakage and abrasion. However, the static and dynamic performance of the RPB has not been confirmed yet. Towards this end, experimental tests and numerical simulations were utilized to study the feasibility of RPB application. Direct shear tests (DSTs) were performed and a DST model and three-sleeper track model with the discrete element method (DEM) were built. The shear strength, settlement, displacement, and acceleration of the RPB were studied. The results show that the RPB has the advantage of increasing the force (stress) distribution and that the smaller crumb rubber size was more suitable for replacing the ballast particles.

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Discrete element modelling of lateral displacement of a granular assembly under cyclic loading

Cited by 66 publications

References 19 publications

Large-scale triaxial and box testing on railroad ballast: a review

Large-scale triaxial and box testing on railroad ballast: a review

Simple particle shapes for DEM simulations of railway ballast: influence of shape descriptors on packing behaviour

Discrete Element Modelling of Rubber-Protected Ballast Performance Subjected to Direct Shear Test and Cyclic Loading

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