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Abstract To investigate the mechanism and manifestation of ballast spoilage, this study introduces a novel approach using a repeated large-scale direct shear test (involving multiple large-scale direct shear tests on the same batch of ballast aggregates) ...
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This paper investigates the effect of particle size distribution and normal pressure on the mechanical response of a ballast bed. Grading curves of ballast layers with different sizes are illustrated to discuss their strength behaviour under various strains to deduce the significant effect on the direct shear performance of the ballast layer ...
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Thus, significant benefits would accrue from a more robust track design having a longer service life and reduced maintenance requirements. This paper presents the results from a laboratory study and explores the potential to achieve this through improving the ballast grading and reducing the ballast shoulder slope.
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Download scientific diagram | Specimens grading for Ballast 1 and Ballast 2 from publication: Laboratory simulation of field loading conditions and maintenance operations | Ballasted track is the ...
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Thus, significant benefits would accrue from a more robust track design having a longer service life and reduced maintenance requirements. This paper presents the results from a laboratory study and explores the potential to achieve this through improving the ballast grading and reducing the ballast shoulder slope.
WhatsApp: +86 18221755073
Grading has long been recognised to critically influence the mechanical behaviour of ballast. To identify the ballast grading for heavy-haul rail track, monotonic and cyclic triaxial tests are ...
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The results show that the type of recovered life-expired ballast used in this study has good performance and similar strength to fresh ballast despite having reduced surface roughness.
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A relatively optimal grading for ballast was proposed to improve its deformation and degradation performances under cyclic loading with high frequency, which would further …
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Download scientific diagram | Grading curve of ballast particles. from publication: Modeling of Coupling Mechanism between Ballast Bed and Track Structure of High-Speed Railway | In this paper, a ...
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Ballast is one of the major sources of construction and maintenance costs for railway tracks. Ballast particle grading critically influences the mechanical behaviour of ballast. In this research, a comparative study has been made to assess the grading performance stipulated in the Bangladesh Railway Ballast Specification (BRS).
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To address this issue, this paper first reviews the means of ballast selection in complex environments across the world. The selection criteria for ballast materials are …
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Both the lateral and longitudinal resistance gradually increase as the ballast grading envelope widens and more fine particles fill in the gaps between the coarse particles. Ballast bed density increases, the ballast bed force is better transmitted, the ballast bed settlement decreases, and the service life of the ballast bed increases. 27
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railway track i.e. life cycle cost of the railway track. Railway ballast grading is one of the most ... Railway Ballast grading have been chosen for research purposes as shown in Table: 3 and Figure 1: 1/5th scaled BR-1,2, JP-1 and AREMA-24(1) ballast grading curve. The characteristics of scaled
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The scope of the research was to assess the influence of grading on ballast breakage and permanent vertical deformation. Breakage and production of fines influence ballast service life, and permanent strain from tamping affects the duration of track alignment. As an approach to simulate the impact from ballast tamping, each test specimen was ...
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The concept of ballast life is presented with a relationship between ballast quality and grading. CP Rail specifications for the selection of a ballast material and the processing of ballast are also presented.
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Ballast grading curves employed in the large scale triaxial tests and the full scale rail track model test. ... in terms of its structural and material behaviour variability throughout its life ...
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The grading is found to affect the behaviour of ballast in that coarser gradings exhibit relatively better strength, resilience and therefore less permanent deformation. However, ballast degradation increases with the overall aggregate size. Therefore, to identify the grading for ballast with different performance objectives, a grey relational
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Ballast cleaning is an efficient recycling maintenance activity used to maximize ballast life and decrease overall maintenance costs. More cost effective operation can be achieved through a better ...
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classes (grading) can be estimated by the abrasion number (AN) of the . ballast material, as shown in Fig. 2. ... service life of ballast materials. It is easy to see that when a more wear .
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The concept of ballast life is presented with a relationship between ballast quality and grading. CP Rail specifications for the selection of a ballast material and the processing of ballast are also …
WhatsApp: +86 18221755073
The grading curve of the ballast is established using the median particle size (d 50) and C u as benchmarks. For well-graded ballast in specification, three d 50 were selected: 36.8 mm, 40.0 mm, and 45.0 mm. In total, 27 sets of non-uniform continuous graded ballast were prepared according to the specification.
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Research into ballast grading will build on and complement recent and current projects investigating the development and role of ballast structure (EP/F062591) and breakage (GR/S14122). Work will commence with an extensive literature …
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RAILROAD BALLAST SIZING AND GRADING. The specified top size and grading (or grain size distribution) of railroad ballast affects its method of production and its performance in track. Both parameters affect any economic evaluation of ballast; as such it is essential to optimize both. The main source for ballast gradings in North America is the ...
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Sub-grade Service Life and Construction Cost of Ballasted, Asphaltic Underlayment and Combination Rail Track Design ... Addition of sub-ballast thickness by 5 cm will raise all-granular track ...
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demonstrate a significant improvement of ballast settlement performance due to changes in the ballast grading, reducing the ballast shoulder slope and two-layered ballast bed. The highest reduction of permanent ballast sett lements about 28 % was reached with a widening the ballast grading using about 20 % of additional mixture 10/45 mm.
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A series of large-scale repeated-load triaxial tests on a crushed metasandstone railway ballast is described. The effects of different gradings on degradation and accumulation of permanent strain are investigated. The material tested was a mechanically strong ballast aggregate with grading curves similar to the envelope curves in the Norwegian railway ballast …
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The tensile strengths of ballast having varying size fractions were examined through the single ballast crushing test, whereby the particle size effect of ballast on its tensile strength was explored.
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The particle size distribution (grading) of ballast aggregates, when determined in accordance with AS 1141.11 and AS 1141.12, shall conform to the requirements set out in Table 1. Sieve Size …
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Aggregate particle shape and size distribution (gradation) are two major considerations in ballasted railroad track design. Superior ballast aggregate shape properties such as by an …
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Ballast material decides the ballast layer life, and further the ballasted track life. In the early days of ... Grading Gradation measurement Drainage, compactness . 5 Physical properties Grading
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