In order to make the decision-making procedures regarding the design and maintenance of ballasted railroad tracks time and cost effective, it is necessary to study and understand the mechanical processes that form the basis of track performance and track deterioration. These mechanical processes can be divided into two categories, namely short-term mechanical processes and long-tern mechanical processes. The former category concerns the instantaneous response of a railway track to one, or a few, train axle passages, whereas the latter category concerns the mechanical processes characterised by a typically quasi-static time-dependency, such as the substructural settlement behaviour under a large number of train axle passages. In this thesis, the mechanical processes specified above are studied by employing continuum models, discrete models, and experimental techniques. The stress and deformation characteristics observed during the cyclic tests have been incorporated into a so-called 'Cyclic Densification Model', that can be used to simulate track deterioration. The Cyclic Densification Model captures only the maximum plastic deformation generated during each load cycle, so that it is possible to evaluate a deformation accumulation by means of relatively large load cycle increments. The model combines a frictional criterion with a compressional criterion to describe the irreversible deformations, whereas the reversible deformations are described by a pressure-dependent hypo-elastic law. Furthermore, a tension cut-off has been included to prevent the occurrence of tensile stresses. The model has been implemented into a finite element method program, employing an Euler backward update algorithm in combination with a consistent tangent stiffness operator. Subsequently, the triaxial experiments discussed above have been used for the calibration of the Cyclic Densification Model. A two-dimensional finite element method simulation has been carried out to analyse track deterioration under a large number of train axle passages. The computed results showed to be in reasonable agreement with the results from in-situ measurements. Several possibilities have been proposed to improve the presented methodology, which may be necessary when extending the current approach towards the three-dimensional modelling of track deterioration.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen


    Exportieren, teilen und zitieren



    Titel :

    The Mechanical Behaviour of Ballasted Railway Tracks


    Beteiligte:
    Suiker, A.S.J. (Autor:in)

    Erscheinungsdatum :

    2001


    Format / Umfang :

    236 Seiten, Bilder, Tabellen, 140 Quellen


    Medientyp :

    Hochschulschrift


    Format :

    Print


    Sprache :

    Englisch





    The mechanical behaviour of ballasted railway tracks

    Suiker, Akke Simon Johanna | TIBKAT | 2002