TY - JOUR A1 - Auersch, Lutz T1 - Characteristics of train passages over slab tracks from measurements and different track-soil models - Damage detection and ground vibration reduction N2 - The train passages over intact or damaged slab tracks on different soils have been calculated by the finite-element boundary-element or the wavenumber-domain method. The influence of track and soil parameters on the distribution of the track displacements and the soil forces has been analysed. The measured and calculated displacement time histories of train passages could be used to identify track damages such as lose sleepers or a lose track plate. The time histories and spectra of the soil forces can explain the measured ground vibration reduction of slab tracks. The calculated displacement and force distributions of slab tracks on continuous soils do not fulfil the Winkler hypothesis and Winkler models should not be used for track analysis. KW - Wavenumber domain KW - Continuous soil KW - Slab track KW - Soil forces KW - Track displacements KW - Track filter KW - Vehicle–track interaction PY - 2020 U6 - https://doi.org/10.1177/0954409719835036 SN - 0954-4097 VL - 234 IS - 2 SP - 142 EP - 160 PB - Sage CY - London AN - OPUS4-50266 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Comparative measurements and calculations of ground vibrations near slab and ballast tracks N2 - Measurements of ground and track vibrations have been performed at a high-speed line in northern Germany. Impacts on the track and the ground, and passages of different trains with different speeds on different tracks have been measured. Transfer functions of the soil are presented and approximated by theoretical soil models. By using these transfer functions, the measured ground vibration between 2 to 64 m distance from the track can be transformed into a load spectrum which can be used for predictions at other sites. The method is compared to the soil-dependent method of an emission spectrum at a certain distance (8 m for example). The influence of train type, speed and track type is discussed on the base of the different emission quantities and the original measurements. The strong influence of the track, ballast track and slab track, is analysed by a theoretical model in wavenumber domain. The response of the track to the passage of the static load is reduced by the stiffness of the slab, the deformation of the track as well as the impulse acting on the soil. Usually, the impulse on the soil should result in a slow quasi-static movement of the soil, slower at further distances. In a heterogeneous soil, however, the impulses from the static loads scatter and keep parts of the higher impulse frequency band. In this case the reduced impulse spectra of the slab track will yield reduced ground vibration in a certain frequency band. Additional (BAM and international) measurements will be used to discuss this and possible other explanations for the different ground vibration differences. T2 - Railways 2018 CY - Sitges, Spain DA - 03.09.2018 KW - Ground vibration measurements KW - Train passages KW - Tran speed KW - Train configuration KW - Ballast track KW - Slab track PY - 2018 AN - OPUS4-46401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Dynamic track-soil interaction – calculations and measurements about slab and ballast tracks N2 - The dynamic behaviour of slab and ballast tracks has been investigated by measurements and calculations. Hammer impacts and train passages have been analysed. Measurements have been performed by geophones (velocity transducers) which have been time-integrated to displacements. The calculations are done in frequency-wavenumber domain for multi-beam-on-continuous soil models. The characteristics of the different tracks and track elements have been established in theory and experiment. The frequency-dependent compliances (displacement transfer functions) show clear rail-on-rail-pad resonances or highly damped track-soil resonances. Compared to the rail and sleeper, the track plate has much lower amplitudes. The slab track has usually the highest rail amplitudes due to soft rail pads. The train passage yields track displacements which are a superposition of the axle loads from the two neighbouring axles of a bogie and from the two bogies of two neighbouring carriages. This global behaviour is characteristic for the track plate of the slab track whereas the rails of the slab and the ballast track behave more local with only one bogie of influence. The measurements agree very well with the theory of the continuous soil in case of the six measured slab tracks and acceptably well for the six measured ballast tracks. The measurements allow to find appropriate model parameters and to check the models, for example the Winkler model of the soil has been found less appropriate as it reacts more locally. KW - Slab track KW - Ballast track KW - Train passage KW - Hammer impact KW - Track-soil interaction PY - 2021 U6 - https://doi.org/10.1631/jzus.A1900651 SN - 1673-565X VL - 22 IS - 1 SP - 21 EP - 36 PB - Zhejiang University Press CY - Hangzhou AN - OPUS4-52107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Measurement of slab track behaviour at different sites N2 - Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory. T2 - 26th International Congress on Sound and Vibration (ICSV26) CY - Montreal, Canada DA - 07.07.2019 KW - Displacements KW - Train passage KW - Slab track KW - Hammer impact KW - Vibration measurements PY - 2019 AN - OPUS4-48495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Measurement of slab track behaviour at different sites N2 - Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory. T2 - 26th International Congress on Sound and Vibration (ICSV26) CY - Montreal, Canada DA - 07.07.2019 KW - Displacements KW - Slab track KW - Train passage KW - Hammer impact KW - Vibration measurements PY - 2019 SN - 978-1-9991810-0-0 SN - 2329-3675 SP - T15RS01_316_1 EP - T15RS01_316_8 PB - Canadian Acoustical Association CY - Montreal, Kanad AN - OPUS4-48498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Slab track behaviour under train passage and hammer impact – Measurements at different sites and calculated track interaction with continuous soils N2 - This contribution intends to give an overview on the vibration behaviour of slab tracks in comparison of measurements and calculations and also by comparison of different track types at more than ten different measuring sites. In theory, tracks on continuous soil are calculated by the frequency-wavenumber domain method. In experiment, geophone measurements are transformed to displacement results. Two aspects of track behaviour are considered, the frequency-dependant compliance of the track, measured by hammer impact, and the deflection under a passing axle load. In theory, the response to a single axle can be calculated, whereas in experiment, only the passage of the whole train can be measured. For comparison of theory and experiment, the calculated deflection under a single axle is superposed to get the response of the whole train. As a result, the slab track characteristics are completely different from the ballast track characteristics where each axle can be seen in the time histories. The slab track has a more global behaviour where only a whole bogie can be found in the track response and moreover, the two neighbouring bogies are not completely separated. The measurement of the different track elements (rail, sleeper, track plate, base layer) and the frequency-dependant compliances with possible resonances yield further information About the properties of the track elements. The calculations show that the soil has the dominant influence on the amplitudes and the width of the track-plate displacements. In the measurement results, the following parameters are analysed: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, voided sleepers, an elastic layer, the mortar layer, and different soils at different places. Finally, a good agreement between measured and calculated results is found for the normal and some special (damaged, floating) slab tracks. KW - Slab track KW - Train passage KW - Hammer impact KW - Compliance function KW - Track deflection PY - 2020 UR - https://iiav.org/ijav/index.php?va=viewpage&vaid=177&id_number=95 U6 - https://doi.org/10.20855/ijav.2020.25.31622 SN - 1027-5851 VL - 25 IS - 3 SP - 341 EP - 354 PB - International Institute of Acoustics and Vibration CY - Gliwice AN - OPUS4-51346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Song, Jiaojiao A1 - Auersch, Lutz T1 - Track-soil calculation and measurement of damaged and repaired slab tracks N2 - Calculation of the behaviour of damaged slab tracks have been performed with ANSYS and with a combined finite-element boundary-element Programme. Different damage lengths have been analysed and the best fit to the measurements has been chosen. T2 - Seminar on Railway Engineering CY - Tongji University Shanghai, People's Republic of China DA - 21.09.2018 KW - Slab track KW - Track damage KW - Boundary element method KW - Train passage PY - 2018 AN - OPUS4-46405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -