列车移动荷载作用下饱和地基的地面振动特性分析

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振动与冲击 ›› 2011, Vol. 30 ›› Issue (6) : 86-92.

论文

列车移动荷载作用下饱和地基的地面振动特性分析

高广运1, 2;李宁1, 2;何俊锋3;高盟4

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Analysis of ground vibration generated by train moving loads on saturated soil

GAO Guang-yun1, 2; Li Ning1, 2;HE jun-feng3;GAO Meng4

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摘要

基于饱和土的Biot波动方程和边界条件，利用Fourier变换和Galerkin法推导出频域内的u-w格式的2.5维有限元方程。把轨道视为饱和地基上的Euler梁，通过沿轨道方向的波数变换将三维空间问题降为平面应变问题。通过解方程首先获得饱和土体频域-波数域的位移解答，然后通过快速Fourier逆变换求得三维时域-空间域内的位移解答。通过计算实例验证了计算模型。建立轨道-地基模型，对饱和地基上列车运行引起的地面振动进行了分析，详细讨论了动力渗透系数、孔隙率、土骨架密度和剪切波速等参数对地面振动传播与衰减的影响规律分析。研究表明；在垂直轨道方向，随着与轨道中心距离增加，加速度幅值和主频迅速衰减；饱和土体动力渗透系数、孔隙率、剪切波速和土骨架密度对地表位移幅值均有较大的影响

Abstract

Based on Biot’s wave propagation equations and boundary conditions, the Galerkin method is used to derive the u-w format finite element equation in the frequency domain by Fourier transform. The track and the attached sleepers are simplified as Euler beams resting on saturated half-space, the wave-number transform in the load moving direction is applied to reduce the three-dimensional (3D) dynamic problem to a two-dimensional (2D) problem. The displacement in frequency-wave number domain is obtained by solving the equations, and the 3D time-space domain displacement of the track and the ground is obtained from the fast Fournier transform. The model of 2.5D FEM is verified by calculation example. The paper has presented a track-ground interaction model. The dynamic response is given to evaluate the ground vibration induced by a moving train on the saturated ground. The effect of the soil parameters (such as permeability coefficient, porosity, soil skeleton density and shear wave velocity) on the attenuation of ground vibration are investigated in detail. The results show that acceleration amplitude and frequency decay quickly with the distance increasing from the track. It is also found that the permeability coefficient of soil, porosity, and shear wave velocity and soil skeleton density have great influence on the ground vibrations

导出引用

高广运;;李宁;;何俊锋;高盟. 列车移动荷载作用下饱和地基的地面振动特性分析[J]. 振动与冲击, 2011, 30(6): 86-92

GAO Guang-yun;;Li Ning;;HE jun-feng;GAO Meng . Analysis of ground vibration generated by train moving loads on saturated soil[J]. Journal of Vibration and Shock, 2011, 30(6): 86-92