EXPERIMENT ON DYNAMIC CHARACTERISTICS AND VIBRATION REDUCTION EFFECT OF STEEL SPRING FLOATING SLAB TRACK

By means of hammer and automatic falling weight excitation device which was developed by Beijing Jiaotong University, the dynamic characteristic and vibration reduction effect experiment of steel spring floating slab track (FST) was made. In the dynamic characteristic experiment, the frequency range was 0 to 400Hz, so that nylon hammer head was chosen, and in the vibration reduction effect experiment, aluminum head was chosen. In the sampling process, using the Variedime-Base transfer function detailed analysis method, the conflict between the accuracy of the time-omain waveform and the frequency resolution of acceleration signal was solved, which improved the analysis precision of the low frequency response. Analyzing the experiment results, some conclusions were obtained: the first-order natural frequency of the FST is 9.8Hz and the top 13 modes of the FST was obtained; under different hammer forces, the 1/3 octave center frequency acceleration transmission loss between the slab and tunnel floor is a constant value above the work frequency (10Hz) of the FST; there is a high vibration mitigation effect of FST, the transmission loss between rail and floor is about 55dB. The experiment is useful for the research of the mitigation performance and operating frequency of the FST.