Study on Evaluation Index of Environmental Vibration Induced by Urban Transit
Index to evaluate environmental vibration induced by urban rail transit are VLzmax and VLmax. Confused calculating methods of evaluation index have affected plan and design of subway line. Influence of overlapping coefficient and frequency weighting curve
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Introduction With the rapid development of rail transit system, rail lines are inevitably go through residential areas and affect normal life of residents around lines [1]. Current standards for evaluating rail transit environmental vibration are “GB10070-88 Standard of Environmental Vibration in Urban Area” [2] and “JGJ/T170-2009 Standard for Limit and Measuring Method of Building Vibration and Secondary Noise Caused by Urban Rail Transit” [3]. The evaluating index are the maximum vibration level of Z direction (VLzmax) and maximum vibration level in dividing frequency of Z direction (VLmax). The current standards don’t give overlapping coefficient about two adjacent waveforms specifically when calculating VLzmax and VLmax. Frequency weighting curve recommended by ISO 2631-1:1985 is adopted when calculating VLzmax according to GB10070-8. This version of frequency weighting curve considering the “fatigue-decreased proficiency limit” caused by vibration is outdate and should be advised. Furthermore, specific calculation method is not given for VLmax in JGJ/T170-2009. Different algorithm for calculating VLmax such as linear averaging method, peak hold method have important effect on the result.
L. Du (&) W. Liu W. Liu M. Ma School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China e-mail: [email protected] W. Liu e-mail: [email protected] W. Liu e-mail: [email protected] M. Ma e-mail: [email protected] © Springer Nature Singapore Pte. Ltd. and Zhejiang University Press 2018 X. Bian et al. (eds.), Environmental Vibrations and Transportation Geodynamics, DOI 10.1007/978-981-10-4508-0_30
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In order to provide guidance for the accurate calculation of evaluating index of environmental vibration, several items are researched. Firstly, a reasonable overlapping coefficient is obtained according to the research of overlapping coefficient of VLzmax and VLmax. Then, a comparative study of different frequency weighting curve versions on VLzmax is conducted and a reasonable frequency weighting curve is recommended. Finally, calculating method for VLmax is recommended according to the results of VLmax in different methods.
Evaluation Index of Environmental Vibration in Urban Areas Measurement and Evaluation Method for VLzmax Standards of GB10070-88 and GB10071-88 point out that vibration level in vertical Z direction should be measured for evaluating environment vibration in urban area. Time weighting value is 1 s and range of frequency weighting is 1–80 Hz [4]. Frequency weighting factor can be seen in GB10070-88 [5]. Measuring point is located outdoors on vibration sensitive place within 0.5 m out of all kinds of buildings, if necessary the measuring point can be located on the floor of building. Calculating VLzmax in the measuring point during the train passing each time and each point should monitor 20 trains continuously. Take the arithmetic average of the 20 VLzmax values as evaluating result and then comparing with the limit value given in GB10070-88 to evaluate environmen
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