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B. Indraratna^1,2, S. Nimbalkar¹ and C. Rujikiatkamjorn³

¹Centre for Geomechanics and Railway Engineering, University of Wollongong, Australia
²ARC Centre of Excellence for Geotechnical Science and Engineering, University of Wollongong, Australia
³School of Civil, Mining and Environmental Engineering, University of Wollongong, Australia

Keywords: ballast, geosynthetics, deformation, drainage, bearing capacity.

Abstract

An efficient transportation infrastructure has become one of the most important priorities for global economic reforms. Railways are designed to provide high speed passenger and heavy haul freight transportation. Ballast is one of the most important constituents of the rail track: however, it experiences excessive deformation and degradation from trains operating at high speeds. In addition, tracks built along coastal areas often undergo large settlements as a result of soft compressible clay deposits. This leads to progressive track deterioration and necessitates frequent and costly track maintenance. The artificial inclusions, such as geogrids, geocomposites, shock mats, and prefabricated vertical drains (PVDs) are often used as attractive design alternatives for track practitioners. However, performances of these inclusions are predominantly governed by their technical specifications in addition to geotechnical characterization of the track substructure, including ballast and subgrade. Therefore, full scale field trials were conducted on instrumented track sections built along the south-east coast of Australia (e.g. Bulli and Singleton). The performance of geogrids and geocomposite was evaluated in terms of specific key parameters, such as stiffness and aperture size of geogrids, placement location of geogrids, as well as subgrade types. It was also proven that the placement of shock mats (rubber pads) in rail tracks lead to the mitigation of particle breakage. An empirical approach to relate ballast strains to the number of load cycles is presented. The aspects of particle degradation and stresses applied by train paths are discussed. The use of PVDs to dissipate the excess pore pressure for increased stability of the soft clay subgrade is presented.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	International Journal of Railway Technology ISSN 2049-5358 IJRT, Volume 2, Issue 3, 2013 Modernisation of Rail Tracks for Higher Speeds and Greater Freight B. Indraratna^1,2, S. Nimbalkar¹ and C. Rujikiatkamjorn³ ¹Centre for Geomechanics and Railway Engineering, University of Wollongong, Australia ²ARC Centre of Excellence for Geotechnical Science and Engineering, University of Wollongong, Australia ³School of Civil, Mining and Environmental Engineering, University of Wollongong, Australia doi:10.4203/ijrt.2.3.1 purchase the full-text of this paper Full Bibliographic Reference for this paper B. Indraratna, S. Nimbalkar, C. Rujikiatkamjorn, "Modernisation of Rail Tracks for Higher Speeds and Greater Freight", International Journal of Railway Technology, 2(3), 1-20, 2013. doi:10.4203/ijrt.2.3.1 Keywords: ballast, geosynthetics, deformation, drainage, bearing capacity. Abstract An efficient transportation infrastructure has become one of the most important priorities for global economic reforms. Railways are designed to provide high speed passenger and heavy haul freight transportation. Ballast is one of the most important constituents of the rail track: however, it experiences excessive deformation and degradation from trains operating at high speeds. In addition, tracks built along coastal areas often undergo large settlements as a result of soft compressible clay deposits. This leads to progressive track deterioration and necessitates frequent and costly track maintenance. The artificial inclusions, such as geogrids, geocomposites, shock mats, and prefabricated vertical drains (PVDs) are often used as attractive design alternatives for track practitioners. However, performances of these inclusions are predominantly governed by their technical specifications in addition to geotechnical characterization of the track substructure, including ballast and subgrade. Therefore, full scale field trials were conducted on instrumented track sections built along the south-east coast of Australia (e.g. Bulli and Singleton). The performance of geogrids and geocomposite was evaluated in terms of specific key parameters, such as stiffness and aperture size of geogrids, placement location of geogrids, as well as subgrade types. It was also proven that the placement of shock mats (rubber pads) in rail tracks lead to the mitigation of particle breakage. An empirical approach to relate ballast strains to the number of load cycles is presented. The aspects of particle degradation and stresses applied by train paths are discussed. The use of PVDs to dissipate the excess pore pressure for increased stability of the soft clay subgrade is presented. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to IJRT purchase this issue (price £70 +P&P)
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