Impact of metro induced ground-borne vibration on urban development
Metro trains are a source of increased noise and vibration, whose negative impact on residential development and production processes can lead to a deterioration in the quality of life or products. Fluctuations from metro trains spread with a certain frequency, depending on the operating train quantity. The level of recorded fluctuations depends mainly on the geological structure of the site, the depth of the line, and the distance to the observer. Instrumental study of the vibration levels on the ground surface is of practical interest in terms of assessing the impact of vibration on the projected buildings or structures, as well as scientific interest in terms of analyzing the spectrum of RMS values of vibration accelerations for each octave band on the ground surface. A four-channel vibrometer was used to measure the levels of vibrations in the overpass between the Belomorskaya and Khovrino stations on the Zamoskvoretskaya line of the Moscow metro, and then the frequency spectra were analyzed. The conclusion is made that the impact at the rail junction significantly contributes to the overall vibration load when the train enters the station, which is confirmed by a sharp increase in vibration levels at the corresponding observation points. The calculation of the natural vibration forms of the tunnel fragment is performed. Analysis of the measurements showed that a moving train excites vibrations in all octave bands, but the maximum levels of vibration acceleration were registered in octaves 16, 31.5 and 63 Hz. This is consistent with the results of the numerical simulation since the calculated natural vibration frequencies of the tunnel fragment are close to those measured on the ground surface.