The Study On Environmental Vibration And Serviceability Induced By Trains On Ballastless Rail

Ballastless track traffic with high-speed railway and dedicated inter-city passenger line as a representative has become a key point in construction of city and inter-city traffic. But the study of environmental vibration resulted from ballastless track traffic lags far behind track transit construction, as well as economic, social and environmental development. The environmental vibration problem caused by track traffic has attracted common concern from various circles of the society, so it has become inevitable to strengthen the study of the environmental vibration and comfort of ballastless track traffic. Currently, the research of the environmental vibration of track traffic is mainly confined to ballasted track, but, of the environmental vibration of ballastless track fewer. There are many evaluations of vibration limit for comfort resulted from qualitative research of track traffic and etc, but few of one resulted from quantitative analysis of ballastless track traffic. Therefore, this paper begins to study around the evaluations of vibration limit for comfort resulted from ballastless track traffic, mainly focusing on the following aspects①Resumptive introduction of the propagation rule of excitation load and vibration of track traffic in soil medium, the impact on adjacent buildings due to the vibration and corresponding vibration limit for comfort in the buildings, as well as a series of subject research status.②Actual measurement of the site vibration due to the train movement on Sui-Yu Railway– the first ballastless track test section; according to the time interval of the measured site vibration acceleration and having analyzed the time domain character of site vibration acceleration, it is found that the site vibration acceleration decays with the distance increase from vibration source, by first-order exponential function; after contrastive analysis between 1/3 times of frequency spectrum, Hilbert spectrum and Hilbert marginal spectrum in the time interval of the measured site vibration acceleration, the main frequency range of the site vibration is 10-120 Hz, of which, Hilbert marginal spectrum can more truly reflect the site vibration caused by moving train.③On the basis of the resumptive introduction of soil wave theory, systematical analysis of the numerical simulation method of vibration propagated in soil. With measured site vibration acceleration as input excitation load, through finite element numerical simulation, by analyzing the propagation rule of train vibration in soil and comparing with the measured acceleration response at corresponding measure point, it is found that the numerical analysis of finite element can better simulate the propagation rule of vibration in soil.④Analysis of finite element analytical theory on the structural vibration of uniform excitation input and multipoint excitation input of load; including setting up structure finite element analytical model based on rigid foundation by use of large mass method, taking measured acceleration for excitation load to analyze the response of building structure to acceleration time interval and spectral characteristic rule under the multi-point excitation, analyzing the impact on the response of building structure to the acceleration, in spectral characteristic, due to the factors, such as the different floors in a building, the different positions in a same floor and train speed and so on.⑤Analysis of the common evaluation methods and standards in the vibration limit for comfort; giving a detailed introduction of the basic theory and calculation method of structure vibration annoyance rate; analyzing the annoyance rate curve and allowable annoyance rate standards under the different working conditions; using the evaluation theory of annoyance rate of vibration limit for comfort to analyze the distribution rule of structural vibration annoyance rate at different positions investigated in buildings, and quantitatively evaluating the building vibration limit for comfort under the excitation of ballastless track train.