轨道结构参数对隧道地面点动力响应的影响分析

首先，以双层弹簧阻尼支撑Timoshenko梁作为轨道结构的力学模型，求得作用于基床表面的荷载；然后，以移动荷载作用下空间体作为地铁列车作用下隧道系统的力学模型，并在其动力响应广义Duhamel积分解的基础上，结合数值拟合的传递函数，给出不同轨道结构参数时地铁列车荷载作用下地面点动力响应的时程和频谱曲线，进而分析轨道结构参数对隧道地面点动力响应的影响。

ANALYSIS OF EFFECT OF TRACK STRUCTURAL PARAMETERS ON DYNAMIC RESPONSES OF GROUND DUE TO METRO TRAIN

The general dynamical response expression of a point in the spatial object is expressed based on the Duhamel integral.In the expression,how to express the transfer function is a key issue when the dynamic point is located on different spaces.As for the subway with running train,firstly,a periodic Timoshenko beam supported with two layers of elastic-damp is adopted as the model of track structure,and the ballast load acting on the ballast surface is derived.Secondly,a space with a hole under inner moving load is adopted as the model of the subway.Using the finite element software ANSYS,the three-dimensional tunnel model is established;and the dynamic responses of the points on the ground surface due to a unit impulse load in the tunnel are computed.The impulse dynamic response function is fitted as the function as plane coordinate x,y and time t,and the corresponding transfer function is obtained through Fourier transform.Thus,the dynamic response of the ground surface due to metro trains is derived.Finally,the effects of track structural parameters on dynamic response of ground due to metro train are calculated and analyzed in time domain and frequency domain.