Experimental and Numerical Study on Ballast Flakiness and Elongation Index by Direct Shear Test

Jing, Guoqing; Ji, Yameng; Qiang, Weile; Zhang, R.

doi:10.1061/(asce)gm.1943-5622.0001791

Cited by 18 publications

(6 citation statements)

References 34 publications

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“…The values of tanφ are in the range of 1.47 and 2.53 for particles with different morphologies. Jing et al 45 found the values of tanφ changed from 1.28 to 2.14 correspondingly. The results of this study agree with the published results 23 , 45 .…”

Section: Resultsmentioning

confidence: 98%

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Discrete Element Analysis of Shape Effect on the Shear Behaviors of Ballast

Hou,

Li,

Song

2023

Sci Rep

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Railway ballast layer is an indispensable component of railway transport. Ballast morphology plays an important effect in ballast-sleeper interaction and the durability of ballast layer. In this study, four types of ballast with different morphological parameters were generated and discrete element method was adopted to investigate the direct shear behaviors. The initial packing states were studied by analyzing the porosities and the normal contact force distributions. The shear results were verified by the reported testing results. On the other hand, one-way ANOVA tests were performed to explore the impact of ballast shape on the initial packing behaviors and the direct shear performance. Results indicated that for all four parameters, aspect ratio (AR), sphericity (Φ), roundness (RD) and convexity (CON), the initial porosities decreased first and increased subsequently along with the increase of the parameters. The four parameters could significantly affect the internal friction inside the assemblies. For each parameter, the larger the parameter, the insignificant the internal friction effect. One-way ANOVA tests revealed that all the four parameters were significant in affecting the initial porosities and the internal friction. Moreover, during the direct shear process, the larger the AR or Φ, the smaller the coordination number, which was mainly ascribed to the ballast shapes.

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Section: Resultsmentioning

confidence: 98%

“…The friction coefficient is in the range of 0.5–0.8 11 , 16 , 24 , 45 . In this study, a friction coefficient of 0.6 was selected to characterize the friction between ballast particles.…”

Section: Dem Modelingmentioning

confidence: 99%

Discrete Element Analysis of Shape Effect on the Shear Behaviors of Ballast

Hou,

Li,

Song

2023

Sci Rep

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“…[82][83][84][85] Therefore, the cubic shape is the best shape for ballast aggregates. 86 The ballast crushing strength and breakage characteristics are highly affected by the flakiness and elongation indices (FI and EI). 87 In addition, the ballast must be washed, and the criterion of ballast fouling level before ballast utilization is obligatory.…”

Section: Ballast Quality and Gradation Controlmentioning

confidence: 99%

“…82–85 Therefore, the cubic shape is the best shape for ballast aggregates. 86 The ballast crushing strength and breakage characteristics are highly affected by the flakiness and elongation indices (FI and EI). 87…”

Section: Solutionsmentioning

confidence: 99%

Railway ballast fouling, inspection, and solutions - A review

Liu

Yang

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part F:

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Ballast fouling occurs when the voids of granular particles are wholly or partially filled by fine particles. Railway ballast fouling is always an inevitable issue related to railway performance and safety in ballasted tracks. This paper presents an overview of the railway ballast fouling mechanism, current works, perspective, and innovation. The paper first reviews the fouling mechanism with different fouling sources and their influence, followed by the fouling indices. Then, fouling inspection methods are reviewed, and the ground penetrating radar is highlighted due to its high efficiency and accuracy. The proposed solutions, including rehabilitation, prevention, reinforcement, and stabilization in the ballasted track, are introduced. Additionally, several perspectives and works for the future are mentioned. Ballast cleaning is a thorough and effective treatment. Ground-penetrating radar inspection and proper evaluation can provide a preview and perspective on ballast cleaning determination.

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“…The insufficient boring test point data cannot fully reflect the ballast bed condition of the entire railway network. With the expansion of railway scale and the increasing shortage of ballast resources (Jing, Huang, Chang, & Qiang, 2017; Morata, 2017), it is urgent to develop a rapid detection technology for ballast bed condition at the railway network level (Niu, 2020), so as to scientifically formulate the repair schedule and reasonably allocate resources and control costs.…”

Section: Introductionmentioning

confidence: 99%

A study on characteristic indexes of railway ballast bed under high-frequency radar

Wang

Peng

Liu

et al. 2023

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PurposeIn this paper, a high-frequency radar test system was used to collect the data of clean ballast bed and fouled ballast bed of ballasted tracks, respectively, for a quantitative evaluation of the condition of railway ballast bed.Design/methodology/approachBased on original radar signals, the time–frequency characteristics of radar signals were analyzed, five ballast bed condition characteristic indexes were proposed, including the frequency domain integral area, scanning area, number of intersections with the time axis, number of time-domain inflection points and amplitude envelope obtained by Hilbert transform, and the effectiveness and sensitivity of the indexes were analyzed.FindingsThe thickness of ballast bed tested at the sleep bottom by high-frequency radar is up to 55 cm, which meets the requirements of ballast bed detection. Compared with clean ballast bed, the values of the five indexes of fouled ballast bed are larger, and the five indexes could effectively show the condition of the ballast bed. The computational efficiency of amplitude envelope obtained by Hilbert transform is 140 s·km−1, and the computational efficiency of other indexes is 5 s·km−1. The amplitude envelopes obtained by Hilbert transform in the subgrade sections and tunnel sections are the most sensitive, followed by scanning area. The number of intersections with the time axis in the bridge sections was the most sensitive, followed by the scanning area. The scanning area can adapt to different substructures such as subgrade, bridges and tunnels, with high comprehensive sensitivity.Originality/valueThe research can provide appropriate characteristic indexes from the high-frequency radar original signal to quantitatively evaluate ballast bed condition under different substructures.

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Experimental and Numerical Study on Ballast Flakiness and Elongation Index by Direct Shear Test

Cited by 18 publications

References 34 publications

Discrete Element Analysis of Shape Effect on the Shear Behaviors of Ballast

Discrete Element Analysis of Shape Effect on the Shear Behaviors of Ballast

Railway ballast fouling, inspection, and solutions - A review

A study on characteristic indexes of railway ballast bed under high-frequency radar

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