Volume 35, Issue 4 (July 2012)

    The Role of Ballast-Fouling Characteristics on the Drainage Capacity of Rail Substructure

    (Received 7 June 2011; accepted 15 February 2012)

    Published Online: 2012

    CODEN: GTJOAD

      Format Pages Price  
    PDF Version 12 $25   ADD TO CART


    Abstract

    The ballast layer is designed to be free draining, but when the voids of the granular medium are wholly or partially filled because of the intrusion of fine particles, the ballast is considered to be “fouled.” To ensure acceptable track performance, it is necessary to maintain good drainage within the ballast layer. This paper critically examines the current methods commonly used for evaluating the degree of ballast fouling and, because of their limitations, a new parameter, “void contaminant index” is introduced. A series of large-scale constant head hydraulic conductivity tests were conducted with different levels of fouling to establish the relationship between the void contamination index and the associated hydraulic conductivity. Subsequently, a numerical analysis was executed to simulate more realistic two-dimensional flow under actual track geometry capturing the drainage capacity of ballast in relation to the void contamination index. In the context of observed test data, the drainage condition of the track could be classified into different categories together with a classification chart capturing the degree of fouling. The contents of this paper have already been considered in track maintenance schemes in the states of Queensland and New South Wales.


    Author Information:

    Tennakoon, Nayoma
    Doctoral Student, Centre for Geomechanics and Railway Engineering, School of Civil Engineering, Faculty of Engineering, Univ. of Wollongong, Wollongong City, NSW,

    Indraratna, Buddhima
    Professor of Civil Engineering, Faculty of Engineering, Univ. of Wollongong, Wollongong City, NSW,

    Rujikiatkamjorn, Cholachat
    Lecturer, Civil Engineering Division, Faculty of Engineering, Univ. of Wollongong, Wollongong City, NSW,

    Nimbalkar, Sanjay
    Research Fellow, Faculty of Engineering, Univ. of Wollongong, Wollongong City, NSW,

    Neville, Tim
    Senior Geotechnical Engineer, Australian Rail Track Corporation Ltd., Broadmeadow, NSW,


    Stock #: GTJ104107

    ISSN: 0149-6115

    DOI: 10.1520/GTJ104107

    ASTM International is a member of CrossRef.

    Author
    Title The Role of Ballast-Fouling Characteristics on the Drainage Capacity of Rail Substructure
    Symposium , 0000-00-00
    Committee D18