列车荷载作用下轨道和地基的动响应分析

分析了列车运动荷载引起的应力波在轨道结构和周围地基中的传播,用动力子结构方法求解了铁路轨道和多层地基的相互作用问题,特别是在模型中考虑了轨枕离散支撑的作用.研究的对象结构包括列车运动荷载和受轨枕支撑的钢轨,以及下面的无限分层黏弹性地基.通过傅里叶变换求解微分形式的支配方程,得到了在频域和波数领域中的钢轨以及周围地基的振动准解析解,而响应时程则通过傅里叶逆变换得到.利用结果可以评估高速铁路列车运行时产生的轨道与周围地基的振动强度;同时提出了一种直观的方法来确定轨道与地基中产生共振时列车运行的临界速度.

Dynamic analyses of track and ground coupled system with high-speed train loads

The wave propagation in track structure and nearby ground induced by the high-speed train operations have been studied herein. The interaction problem of train track and multi-layered ground has been solved by applying dynamic substructure method. The studied dynamics system comprises two substructures: one is the moving train and the track structure which is supported by sleepers; and the other is the layered visco-elastic ground which is subject to the discretely distributed loads from sleepers. Two components are coupled with the continuum condition at the contact interface. The track and nearby ground dynamic responses in frequency and wave-number domain have been obtained by solving the gqverning differential equations with the Fourier transform method. The time histories of responses also are available from the inverse Fourier transform. From the numerical study, the vibration intensities of track structure and nearby ground can be evaluated for the high-speed train operation. At the same time, an effective method has been proposed to estimate the critical speed of train running on track ground for possible resonance, which is of paramount importance to ensure the safety of high-speed train operations.