埋置移动荷载作用下饱和成层地基-梁耦合系统动力响应分析

Dynamic response of the layered saturated foundation-beam coupling system subjected to a buried moving load

针对地铁列车运行中引起的地表振动问题,研究了埋置移动荷载作用下饱和成层地基-梁耦合系统的动力响应。将地基土体采用Biot饱和多孔介质理论来模拟,将地下轨道结构简化为埋置无限长Euler-Bernoulli梁,埋置移动荷载作用在梁上。并采用传递透射矩阵法(TRM法)考虑地基的成层性。利用Fourier变换及逆变换,结合梁与土体间的力与位移连续条件,得到了地基在时间空间域内的动力响应解答。当饱和成层地基退化为均质黏弹性地基时,所得解与已有解能很好地吻合。最后,通过数值算例分析了梁的刚度﹑埋置深度及荷载移动速度、频率等因素对地表振动的影响。

In order to investigate the surface vibration induced by the subway,a layered saturated foundation-beam coupling model is established.The soil is assumed to be a fully saturated porous elastic medium obeying Biot's dynamic porous elastic theory and the layered property is considered by the TRM method.The Euler-Bernoulli beam is adopted to model the track structure in the foundation.The train load is simplified as a harmonic load moving at a constant speed.Combined with the con-tinuity conditions of force and displacement between the beam and the soil,the general solutions are obtained by using the Fourier transform and the Fourier inverse transform.When the layered saturated foundation is reduced to a viscoelastic foundation,the results obtained in this paper ware in good agreement with the current viscoelastic solution.At last,the influence of the stiffness and depth of the beam,the load speed and frequency to the dynamic response of the foundation-beam coupling system is discussed.