高速铁路过渡段路基自振频率的模态分析与试验

通过建立有限元模型,对武广(武汉—广州)高速铁路过渡段路基进行模态分析,获得路基的竖向自振频率.同时,在路基中埋设传感器,获取环境激励路基振动时程曲线及列车过后的衰减自由振动波形,分别采用傅里叶变换原理及最大熵谱法对其进行自振频率分析.研究结果表明:模态分析与现场实测所获得的路基自振频率基本相近,可以采用模态分析来获得路基的自振频率；采用最大熵谱法对现场实测的路基衰减自由振动波形进行频谱分析更易于分析路基的固有频率,并且可以得到较准确的测试结果.

Modal analysis and experiment research on natural frequencies of transition section subgrade of high-speed railway

Based on the finite element model,the vertical natural frequency of subgrade was obtained through the modal analysis of the subgrade transition section of Wu-Guang(Wuhan-Guangzhou) High-speed Railway.The time history of vibration and damped free vibration waveform of the subgrade were acquired by ambient excitation and train loads excitation,and the nature frequency was obtained through principle of Fourier transform and maximum entropy spectrum method.The result of modal analysis was chosen in actual measurement.The results show that the model is correct and the natural frequency of the subgrade can be acquired through modal analysis.In the field measurement,the accurate test results are easy to be obtained through frequency spectrum analysis in the maximal entropy spectrum method of the damped free vibration waveform of the subgrade.