A sequence of models currently in use by DB Systemtechnik has been described that allow to estimate the acoustic emission for a typical tunnel on the German high-speed network given a certain train and tunnel shape, train speed, tunnel length and exit portal geometry. The tools presented in this paper allow a prediction of the complete micro-pressure wave pressure signals in the time domain. Unsteady 3d-CFD simulations were used to investigate the generation of the compression wave. Some results ranging from the worst-case scenario of a plane vertical wall up to a 70 m long portal hood are shown and compared. The wave steepening process was modelled using steady and, unsteady friction parameters. Both parameters were adjusted to fit to full-scale measurements in German tunnels equipped with slab track. A good agreement in the steepened pressure signal (pressure amplitude as well as pressure gradient) was found. While the steady friction parameter λ was the same as in the Japanese model, the unsteady friction parameterεus was significantly smaller than reported by RTRI. This indicates that the tunnel interior design might have a bigger influence on the steepening than expected. The emitted micro-pressure wave signals were calculated from the steepened compression wave by the far-field approximation of a vibrating circular piston solution. The portal specific solid angles were adjusted to full-scale measurements at several existing portals. A moderate dependence of the solid angle on the magnitude of the pressure gradient was observed for different portal shapes. For a conservative prognosis, the smallest values of the empirically found solid angles should be used. Finally a procedure of an acoustical assessment was presented. This assessment procedure will be the basis of all tunnels either in the planning phase or under construction at the present in Germany. It was documented in a new module within the DB guideline Ril 853 "Eisenbahntunnel planen, bauen und instand halten", which was put into force on February 1st 2013. With this assessment procedure a well balanced protection level was reached, which gives a practicable basis for the successful approval of new infrastructure projects. In an early stage of infrastructure projects, the design of measures can be approved and thus planning reliability is achieved. Acoustical problems occurring after a high-speed line goes into Operation can thus be avoided.


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    Titel :

    Regulation of micro-pressure wave emissions for german high-speed railway tunnels


    Beteiligte:
    Hieke, Michael (Autor:in)


    Erscheinungsdatum :

    2013


    Format / Umfang :

    13 Seiten, 10 Bilder, 1 Tabelle, 13 Quellen



    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch