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000022473 005__ 20170622150016.0
000022473 04107 $$aeng
000022473 046__ $$k2015-05-25
000022473 100__ $$aAuersch, Lutz
000022473 24500 $$aFAST COMPUTATION OF TRAIN-INDUCED VIBRATIONS IN HOMOGENEOUS AND LAYERED SOILS

000022473 24630 $$n5.$$pComputational Methods in Structural Dynamics and Earhquake Engineering
000022473 260__ $$bNational Technical University of Athens, 2015
000022473 506__ $$arestricted
000022473 520__ $$2eng$$aThe computation of the wave propagation in homogeneous and layered soils can be performed by a numerical integration in wavenumber domain. The numerical difficulties of an infinite integral and an integrand with poles can be solved. But if this computation must be repeated for many distances, many frequencies, many loads, or many soil models, it becomes a time consuming task which is not acceptable for a user-friendly prediction tool for railway induced ground vibration. Therefore, an approximate method for the computation of the wave field has been developed. The computation consists of several steps. At first, an approximate dispersion profile is calculated according to rules which have been derived from exact solutions. Secondly, the dispersion is used to achieve the amplitude for a certain frequency and a certain distance by calculating the approximate solution of a corresponding homogeneous half-space. Thirdly, three layer corrections are added which include lowfrequency near-field effects, high-frequency far-field effects, and a resonance amplification around the layer frequency. This procedure yields the wave field due to a point load. For a train load, many of these point-load responses have to be summed up, and a frequencydependant reduction factor has to be multiplied to incorporate the effect of the load distribution along and across the track. - The prediction method is applied to real sites, and the appropriate soil models are identified by approximating the measured transfer functions (frequency-dependant amplitudes) which is presented as an alternative to the approximation of the dispersion (frequency-dependant wave velocities). These examples demonstrate the general behavior of layered soils: the low amplitudes of the stiff half-space at low frequencies, the high amplitudes of the softer layer at high frequencies, the strong increase of amplitudes and a possible resonance amplification at mid frequencies. The material damping of the layer yields a strong attenuation of the amplitudes with the distance for high frequencies. The response depends strongly on the resonance or layer frequency which is shown for different layer depths and velocities always in good agreement with measurements. The layer frequency can be of immense influence if train-speed effects are analysed in a layered soil. The good agreement with many measurements in this contribution as well as in the 

000022473 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000022473 653__ $$aTrain-induced ground vibration, transfer functions of layered soil, dispersal soil method, frequency-dependant half-space, layer resonance frequency, train speed effects

000022473 7112_ $$aCOMPDYN 2015 - 5th International Thematic Conference$$cCrete (GR)$$d2015-05-25 / 2015-05-27$$gCOMPDYN2015
000022473 720__ $$aAuersch, Lutz
000022473 8560_ $$ffischerc@itam.cas.cz
000022473 8564_ $$s3058593$$uhttp://invenio.itam.cas.cz/record/22473/files/C959.pdf$$yOriginal version of the author's contribution as presented on CD, section: 
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000022473 962__ $$r22030
000022473 980__ $$aPAPER