移动荷载作用下饱和地基上板式轨道动力分析

摘要

The dynamic responses of a slab track on the poroelastic half-space subjected to moving train loads are investigated by a semi-analytical approach. The track model is described as an upper Euler beam to simulate rails and a lower Euler beam to model the slab. Railpads between the rails and slab are represented by a continuous layer of springs and dashpots. It is assumed that the interface of the slab and the poroelastic half-space soil medium is permeable. A series of point loads are formulated to describe the moving train loads. The governing equations of track-ground system are solved using the Fourier transform. The dynamic responses in time domain are obtained through the fast Fourier transform (FFT). Effects of the soil intrinsic permeability and the stiffness of slab on soil displacement and acceleration have been carefully analyzed. Numerical results show that the vibration responses of the ground are significantly affected by the fluid phase in the soil medium and soil dynamic responses decrease with increasing stiffness of the slab.%采用半解析法研究了列车荷载作用下板式轨道-下卧饱和土体系统的动力响应问题.采用双层弹性Euler梁来模拟板式轨道中的钢轨和轨道板,采用弹簧-阻尼器来模拟轨下垫圈.列车荷载采用一系列移动的点荷载来模拟,下卧土体采用多孔饱和半空间模型,并假定半空间土体表面与轨道板接触面完全透水.利用Fourier变换方法在变换域内求解轨道和土体的控制方程,饱和土体动力响应在时域内的结果通过快速Fourier变换求得.文章中主要研究了轨道板刚度和土体渗透系数对土体位移和加速度响应的影响.研究表明,土体中液相介质的存在会对土体的振动响应产生很大影响,且适当增大轨道板刚度可有效控制高速列车引起的土体动力响应.