Current research into ballasted rail tracks: model tests and their practical implications

Indraratna, Buddhima; Sun, Qideng; Ngo, Ngoc Trung; Rujikiatkamjorn, Cholachat

doi:10.1080/13287982.2017.1359398

Cited by 16 publications

(13 citation statements)

References 58 publications

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“…-laboratory testing [1, 4, 6-8, 10, 12, 15-18, 24, 26, 29, 30, 33, 38, 45, 47, 53, 55, 56], -DEM (discrete element method) simulations and/or 3D grain shape improvements [10,11,12,22,24,37,53,55], -FEM (finite element method) simulations [10], -field tests [3,16,46,48,50]. The noticed researchers behoved with the main subfields without the requirement of fullness:…”

Section: Methodsmentioning

confidence: 99%

Special Laboratory Testing Method for Evaluation Particle Breakage of Railway Ballast Material

Fischer

2018

STP

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Purpose. There are special, standardized laboratory test methods to evaluate railway ballast particle breakage; they are the Los Angeles and the Micro-Deval abrasion test. The authors opine that these methods aren't the most adequate methods to assess the real ballast particle degradation because in reality never occurs these kinds of stresses and strains (i.e. particles in a rotating drum with or without steel balls and with or without water). A new laboratory test procedure is needed. The authors attempted to configure an adequate one in 2014, it is detailed in the paper, as well as the initial results and improvement possibility. This test method is related to dynamic pulsating test, the particle size distributions (PSD) had to be determined before and after fatigue. In 2017-2018 the research is supported by ÚNKP-17-4 program. Methodology. Multi-level steel box is utilized with a special layer structure, detailed in the paper. Five different types of railway ballast samples were tested. PSDs were defined, and regarding to the results relationship between ballast particle degradation values (according to Los Angeles and Micro-Deval abrasion tests, as well as this newly developed laboratory test method) was searched, as well as time interval between necessity railway ballast cleaning work was also calculated. Findings. The authors sentenced the results regarding to the self-developed laboratory test method that is able to assess the particle degradation and time interval between railway ballast cleaning work more precisely related to the real railway operation circumstances. Relationship was determined between particle breakage according to standardized and unique (non-standardized) laboratory test methods. Originality. The paper summarized the results a newly developed laboratory test method for evaluation of the degradation of railway ballast particles. Practical value. It sentenced the possibility to improve the measurements and assessments regarding to the research phase supported by the ÚNKP-17-4 project.

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Section: Methodsmentioning

confidence: 99%

Special Laboratory Testing Method for Evaluation Particle Breakage of Railway Ballast Material

Fischer

2018

STP

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“…During train operations the track progressively deteriorates due to: (i) the lateral spreading and settlement of ballast or sub-ballast layers because of inadequate confinement [2,4]; (ii) ballast deteriorations caused by breakage of sharp edges and angular corners, the intrusion of fine particles, and mud-pumping from the layers of soft soil lying below, all of which seriously compromise its particle angularity, shear strength and hydraulic conductivity [2,[5][6][7]. Such track deterioration leads to costly and frequent maintenance, especially when the heavy haul tracks undergo heavier axle loads and higher speeds [8,9]; for example, in New South Wales, Australia alone the cost of track maintenance for ballast-related work is estimated to be around 14-15 million dollars per year [10]. In addition to the repeated loads exerted by moving wheels, rail structures are commonly subject to dynamic impact forces of high magnitude produced by rail irregularities (e.g., corrugations, imperfect welds, rail dips) as well as imperfections such as wheel flats.…”

Section: Introductionmentioning

confidence: 99%

“…FEM modelling for rubber tire-reinforced capping layer: (a) Track geometry with rubber tires reinforced capping layer; (b) FEM mesh of ballasted railway track; (c) FEM mesh of rubber tires (modified after Indraratna et al[8]). …”

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confidence: 99%

Use of Geogrids and Recycled Rubber in Railroad Infrastructure for Enhanced Performance

Indraratna

Ngo

et al. 2019

Geosciences

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Railway tracks are conventionally built on compacted ballast and structural fill layers placed above the natural (subgrade) foundation. However, during train operations, track deteriorations occur progressively due to ballast degradation. The associated track deformation is usually accompanied by a reduction in both load bearing capacity and drainage, apart from imposing frequent track maintenance. Suitable ground improvement techniques involving plastic inclusions (e.g., geogrids) and energy absorbing materials (e.g., rubber products) to enhance the stability and longevity of tracks have become increasingly popular. This paper presents the outcomes from innovative research and development measures into the use of plastic and rubber elements in rail tracks undertaken at the University of Wollongong, Australia, over the past twenty years. The results obtained from laboratory tests, mathematical modelling and numerical modelling reveal that track performance can be improved significantly by using geogrid and energy absorbing rubber products (e.g., rubber crumbs, waste tire-cell and rubber mats). Test results show that the addition of rubber materials can efficiently improve the energy absorption of the structural layer and also reduce ballast breakage. Furthermore, by incorporating the work input parameters, the energy absorbing property of the newly developed synthetic capping layer is captured by correct modelling of dilatancy. In addition, the laboratory behavior of tire cells and geogrids has been validated by numerical modelling (i.e., Finite Element Modelling-FEM, Discrete Element—DEM), and a coupled DEM-FEM modelling approach is also introduced to simulate ballast deformation.

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“…Australia is at the pinnacle in relation to heavy haul train operations often involving 3-5-km-long trains with axle loads up to 40 tonnes [18]. However, these heavy freight trains demand safe and economic track design to withstand the large cyclic and impact loads, while protecting the formation soils from being subjected to shear failure and excessive settlements [29,54,59]. The ballast layer consists of natural or crushed granular material with a typical thickness of 250-350 mm that is placed beneath the track superstructure and above the sub-ballast and sub-grade providing structural support against the stresses imposed by moving wheel loads.…”

Section: Introductionmentioning

confidence: 99%

“…Such deterioration of ballast can lead to frequent and costly maintenance, especially as the heavy haul tracks are subjected to higher speeds and heavier axle loads [3,29]. In this regard, the use of artificial inclusions including geogrids, geocomposites and recycled rubber sheets to mitigate the deformation and degradation of ballast has become popular in recent years [5,6,8,12,[46][47][48]67], among others.…”

Section: Introductionmentioning

confidence: 99%

Application of geoinclusions for sustainable rail infrastructure under increased axle loads and higher speeds

Indraratna

Ferreira

et al. 2018

Innov. Infrastruct. Solut.

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Ngoc Trung, "Application of geoinclusions for sustainable rail infrastructure under increased axle loads and higher speeds" (2018). Faculty of Engineering and Information Sciences -Papers: Part B. 1988. Abstract AbstractGiven the ongoing demand for faster trains for carrying heavier loads, conventional ballasted railroads require considerable upgrading in order to cope with the increasing traffic-induced stresses. During train operations, ballast deteriorates due to progressive breakage and fouling caused by the infiltration of fine particles from the surface or mud-pumping from the underneath layers (e.g. sub-ballast, sub-grade), which decreases the load bearing capacity, impedes drainage and increases the deformation of ballasted tracks. Suitable ground improvement techniques involving geosynthetics and resilient rubber sheets are commonly employed to enhance the stability and longevity of rail tracks. This keynote paper focuses mainly on research projects undertaken at the University of Wollongong to improve track performance by emphasising the main research outcomes and their practical implications. Results from laboratory tests, computational modelling and field trials have shown that track behaviour can be significantly improved by the use of geosynthetics, energy-absorbing rubber mats, rubber crumbs and infilled-recycled tyres. Fullscale monitoring of instrumented track sections supported by rail industry (ARTC) has been performed, and the obtained field data for in situ stresses and deformations could verify the track performance, apart from validating the numerical simulations. The research outcomes provide promising approaches that can be incorporated into current track design practices to cater for high-speed freight trains carrying heavier loads.

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Current research into ballasted rail tracks: model tests and their practical implications

Cited by 16 publications

References 58 publications

Special Laboratory Testing Method for Evaluation Particle Breakage of Railway Ballast Material

Special Laboratory Testing Method for Evaluation Particle Breakage of Railway Ballast Material

Use of Geogrids and Recycled Rubber in Railroad Infrastructure for Enhanced Performance

Application of geoinclusions for sustainable rail infrastructure under increased axle loads and higher speeds

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