Numerical analysis of ground surface vibration induced by underground train movement

The purpose of this study is the simulation of train movement and calculation of ground surface vibration induced by train movement in the subway tunnel. Tehran metro line 4 that is located in a populated area was considered as a case study. For simulation of train movement, effective factors on dynamic load magnitude and frequency have been studied and variation of wagon force in a longitude model is considered. Then Fourier amplitude spectrum was computed by means of Fast Fourier Transformation (FFF) of the dynamic train load and then the frequency range of train load was determined. In the next step, low energy frequencies were filtered and the dynamic load as a point load was applied on the numerical model of the tunnel and the ground surface vibration was determined. Finally, the result of the numerical model is verified by Metrikine and Vrouwenvelder's analytical model. Comparisons of numerical and analytical solutions shows that the numerical results have a good agreement with the analytical output and the maximum displacement in the horizontal and vertical directions are 3.75 and 5.25 mm, respectively. (C) 2011 Elsevier Ltd. All rights reserved.