水泥混凝土路面脱空板的自振频率试验分析

Experiment Research on Natural Frequencies of Cavity Slab of Cement Concrete Pavement

水泥混凝土路面板脱空程度与其振动特征有较好的相关性,为准确获取路面板的竖向自振频率,通过布设传感器,获取不同脱空程度路面板在环境激励振动时程曲线及瞬态激励后的衰减自由振动波形,并对其分别采用傅里叶变换原理及最大熵谱法进行自振频率分析.研究结果表明,在进行自振频率测试及分析时应采用多种方法综合分析,以免造成误判;瞬态激励下路面板的振动幅值比环境激励情况下的振动幅值大,可以采用最大熵谱法对激励后的自由测试衰减振动进行分析,结果更为清晰准确.这些研究,可为今后路面板的脱空检测及自振频率分析提供一定参考.

These have good correlation between cavity degree of cement concrete pavement slab and its vibration characteristics. To accurately obtain the vertical vibration frequency of the concrete pavement slab, the time history of vibration and damped free vibration wave form of the pavement slab of different cavern area were acquired by ambient excitation and transient excitation, the nature frequency was obtained through principle of fourier transform and maximum entropy spectrum method. The result shows that the vertical natural frequency of the pavement slab should be acquired through comprehensive analysis of various methods in the field measurement. The vibration amplitude of pavement slab in case of transient excitation is higher than that in case of ambient excitation, the accurate and clear test results are easy to be obtained through frequency spectrum analysis in the maximum entropy spectrum method of the damped free vibration waveform of the pavement slab. These researches will provide certain reference for cavity detection and natural frequency analysis of pavement slab in the future.