Skip to main content
placeholder image

Implications of ballast breakage on ballasted railway track based on numerical modelling

Conference Paper


Download full-text (Open Access)

Abstract


  • Large and frequent cyclic train loading from heavy haul and passenger trains often leads to progressive

    track deterioration. The excessive deformation and degradation of ballast and unacceptable

    differential settlement of track and/or pumping of underlying soft subgrade soils necessitate

    frequent and costly track maintenance. A proper understanding of load transfer mechanisms and

    subsequent deformations in track layers is the key element for safe and economical track design and

    optimum maintenance procedures. Many simplifi ed analytical and empirical design methods have

    been used to estimate the settlement and stress-transfer between the track layers. However, these

    design methods are based on the linear elastic approach, and often only give crude estimates.

    Given the complexities of the behaviour of the composite track system consisting of rail, sleeper,

    ballast, sub-ballast and subgrade subject to repeated traffi c loads in a real track environment, the

    current track design techniques are overly simplifi ed. The track design should also account for the

    deterioration of ballast due to breakage and subsequent implications on the track deformations.

    Considering this, an elasto-plastic constitutive model of a composite multi-layer track system is

    proposed. Constitutive models and material parameters adopted in this numerical model are discussed.

    A hardening soil model with a non-associative fl ow rule is introduced to accurately simulate

    the strain-hardening behaviour of ballast. The breakage of ballast observed in large scale triaxial

    tests is also simulated based on this model. In conjunction, numerical simulations are also performed

    using a two-dimensional plane-strain fi nite element analysis (PLAXIS) capturing the effects

    of ballast breakage and track confi ning pressure. The paper also demonstrates the advantages of

    the proposed elasto-plastic fi nite element simulations when compared to conventional analytical

    methods used by practitioners that are primarily based on a linear elastic approach.

Publication Date


  • 2011

Citation


  • Indraratna, B. & Nimbalkar, S. (2011). Implications of ballast breakage on ballasted railway track based on numerical modelling. In N. Khalili & M. Oeser (Eds.), 13th International Conference of the International Association for Computer Methods and Advances in Geomechanics (pp. 1085-1092). Australia: Centre for Infrastructure Engineering and Safety.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1943&context=engpapers

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/906

Start Page


  • 1085

End Page


  • 1092

Place Of Publication


  • Australia

Abstract


  • Large and frequent cyclic train loading from heavy haul and passenger trains often leads to progressive

    track deterioration. The excessive deformation and degradation of ballast and unacceptable

    differential settlement of track and/or pumping of underlying soft subgrade soils necessitate

    frequent and costly track maintenance. A proper understanding of load transfer mechanisms and

    subsequent deformations in track layers is the key element for safe and economical track design and

    optimum maintenance procedures. Many simplifi ed analytical and empirical design methods have

    been used to estimate the settlement and stress-transfer between the track layers. However, these

    design methods are based on the linear elastic approach, and often only give crude estimates.

    Given the complexities of the behaviour of the composite track system consisting of rail, sleeper,

    ballast, sub-ballast and subgrade subject to repeated traffi c loads in a real track environment, the

    current track design techniques are overly simplifi ed. The track design should also account for the

    deterioration of ballast due to breakage and subsequent implications on the track deformations.

    Considering this, an elasto-plastic constitutive model of a composite multi-layer track system is

    proposed. Constitutive models and material parameters adopted in this numerical model are discussed.

    A hardening soil model with a non-associative fl ow rule is introduced to accurately simulate

    the strain-hardening behaviour of ballast. The breakage of ballast observed in large scale triaxial

    tests is also simulated based on this model. In conjunction, numerical simulations are also performed

    using a two-dimensional plane-strain fi nite element analysis (PLAXIS) capturing the effects

    of ballast breakage and track confi ning pressure. The paper also demonstrates the advantages of

    the proposed elasto-plastic fi nite element simulations when compared to conventional analytical

    methods used by practitioners that are primarily based on a linear elastic approach.

Publication Date


  • 2011

Citation


  • Indraratna, B. & Nimbalkar, S. (2011). Implications of ballast breakage on ballasted railway track based on numerical modelling. In N. Khalili & M. Oeser (Eds.), 13th International Conference of the International Association for Computer Methods and Advances in Geomechanics (pp. 1085-1092). Australia: Centre for Infrastructure Engineering and Safety.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1943&context=engpapers

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/906

Start Page


  • 1085

End Page


  • 1092

Place Of Publication


  • Australia