Role of Initial Particle Arrangement in Ballast Mechanical Behavior

Qian, Yu; Lee, Seung Jae; Tutumluer, Erol; Hashash, Youssef M. A.; Ghaboussi, Jamshid

doi:10.1061/(asce)gm.1943-5622.0001074

Cited by 37 publications

(21 citation statements)

References 26 publications

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“…If a clump shape is used to simulate railway ballast, it should be able to generate packings at field porosity as well as lab porosities. While field porosities are hard to measure, porosity = 0.405 is reported in the literature, see [41], which state: "similar field densities were reported in a previous study:" [18]. For lab testing, usually lower porosities are reported.…”

Section: Introductionmentioning

confidence: 61%

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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Section: Introductionmentioning

confidence: 61%

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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“…Each layer is exposed to 40 blows. Mishra et al [23], Qian et al [39,52] used electric jackhammer to copmact ballast sample layers. The authors applied four lifts to ballast sample with 4 s of compaction time for each lift.…”

Section: Sample Compactionmentioning

confidence: 99%

“…From the literature, Qian et al [39,52] used a value of strain rate of 0.0167% strain/second in their large-scale triaxial testing of railroad ballast. However, there are number of publications in the literature used a strain rate quite close to the common value based on the equipment limitation like 0.0197% [20], 0.0117% [10] and 0.00833% [32] strain/second.…”

Section: Strain Ratementioning

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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“…Most of the DEM models for railroad ballast in the literature, were used to calibrate material properties or validate experimental tests. For example, particle crushing test [5], uniaxial test [6], triaxial test [7], direct shear test [8] and box test [5].…”

Section: Introductionmentioning

confidence: 99%

INVESTIGATING THE BEHAVIOR OF RAILROAD BALLAST IN A BOX TEST UNDER SINUSOIDAL & SIMULATED TRAIN LOADING

Alabbasi¹,

Hussein²

2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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The use of railway transportation systems has been increased throughout the years. Conventional ballasted tracks have been widely used in many countries around the world. Ballast material is the basic element in ballasted track, it degrades and deforms after service. Therefore, periodical ballast maintenance is required which is a cost and time expensive activity. Understanding of ballast behavior leads to efficient design and maintenance. From the literature, Discrete Element Method is used extensively to understand the behavior of railroad ballast through box test. However, most researches in the literature simulate the train loading as a pure continuous sinusoid unlike the actual loading induced by the trains. This paper aims to show the influence of simulated loading of moving train on the dynamic behavior of railroad ballast using box test via DEM. The paper utilizes the theory of Beam on Elastic Foundation to simulate a more realistic loading on railroad ballast. The results from the simulated train load are compared with those from a sinusoidal load. The results show a difference up to 6.89% between simulated train and sinusoidal loading.

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Role of Initial Particle Arrangement in Ballast Mechanical Behavior

Cited by 37 publications

References 26 publications

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

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

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

INVESTIGATING THE BEHAVIOR OF RAILROAD BALLAST IN A BOX TEST UNDER SINUSOIDAL & SIMULATED TRAIN LOADING

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