In Situ Experiment And Analysis Of Environmental Vibration Induced By Urban Subway Transit

With the development of social economy and the raise of people's living quality, the elevated railroad has brought us with great convenience, at the mean time it also can cause environmental vibration which the influence to human's life and work environment has aroused widely attention. In this paper, the propagation, the regulations of vibration attenuation are studied by both in situ experimental and simulation method, based on the observed data of the first and second line in a subway. The key points of this paper can be concluding as follows:1. The regulations of vibration attenuation of a subway are concluded by analyzing the situ data. In the zone near rail, the high-frequency vibration is stronger than other weight, and in the zone far away from railway, the results is opposite. The vibration in vertical weight attenuates more slowly than in horizontal weight, and the amplitude in vertical weight is higher than in horizontal weight. The vibration propagation is prodigious influenced by geological condition and the depth of tunnel. At last, linear method is carried to study the attenuation empirical formal of VL.2. The discrete sampling value of field track vibration acceleration wave is transformed by FFT and analyzed by deterministic analysis. One degree of freedom simplified model is used for train and the kinematic equilibrium differential equation is deduced to simulate the vertical wheel system. Then, the expression of the vertical train vibration load is deserved.3. The interpolation formula of the second-order transmitting boundary is deduced. Adopting the second-order transmitting boundary to erase the effect of reflecting wave in model boundary, while simulation the infinite continuous medium.4. Using the Finite-element software ANSYS, two dimensions soil-tunnel model is established, and the dynamic response are analyzed in multiple situation .At last, the characteristic of subway environmental vibration is concluded, which could be used for reference in vibration control and buffer design of the ground structure.5. Contrast measuring results to numerical calculating results, they are inosculated. So, the results of calculating are creditable.