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Abstract 2.5D finite element equation for elastic waves of transversely isotropic soil is derived from means of 2.5D finite element method(FEM) from elastic constitutive equation of the transversely isotropic soil. The track is simplified as an Euler beam resting on the transversely isotropic ground. Through finite element discretization，the track structure and the foundation in a section perpendicular to track direction are modeled with 8-node elements，in which each node consists of three degrees of freedom. A 3D problem is reduced to a plane strain problem；and the results can be obtained by inverse fast Fourier transformation(FFT). Dynamic responses of the ground are analyzed based on typical parameters of soil in Shanghai and Beijing areas. The results indicate that the amplitude of acceleration and displacement response amplitude caused by train traveling in Beijing area were higher than that in Shanghai area，respectively. With the distance increase to the track center，dynamic response frequencies of the ground in both areas are declined to the free vibration frequency of simple harmonic vibration；so the filtering of transversely isotropic soil is obvious. Transmission of dynamic wave in soft soil layer costs more energy than hard soil. The rebound phenomenon in the attenuation curve of the ground vibration has the tendency to increase，which is closely relevant to the parameters of the soil and the train speed.
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Received: 08 June 2012
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2013, Vol. 32 
