探地雷达检测铁路道床翻浆冒泥的时频域特征

Time-Domain and Frequency-domain Characteristic of Ballast Mud Pumping in GPR Inspection

为研究铁路道床翻浆冒泥病害探地雷达图像的识别,通过在标准铁路轨道上设置翻浆冒泥至道砟面和未至道砟面两种病害模型,研究两种翻浆冒泥病害随时间和含水率变化的时域及频域特征。通过时间域和频域的A扫描数据对比及B扫描数据分析得到:翻浆冒泥至道砟面时在剖面图和时间域波形上形成强反射并能轻易分辨,而未至道砟面反应相对微弱;道床翻浆冒泥使频谱中的特征频点幅值减弱,频域幅值变化百分数在道床翻浆冒泥中显著高于时间域的变化。这两个结论说明在识别探地雷达铁路路基道床翻浆冒泥病害时,应同时结合频域特征点的变化来判断。

In order to study the GPR image recognition of mud pumping in railway ballast bed,the time-domain and frequency-domain characteristics changing with time and water content were studied by setting the mud pumping models above and below the ballast surface on the standard railway track.By comparison and analysis of A-scan data in the time and frequency domain and B-scan data,conclusions are presented:the section plan and waveform in time domain of ballast mud pumping to surface is strong and can be easily distinguished,but it is obviously weaker in another condition;ballast mud pumping will cause the amplitude of characteristics point in frequency spectrum weak,and the percentage of weak in two conditions ballast mud pumping is significantly higher than the time domain.These two conclusions show that in recognition of GPR in railway ballast bed mud pumping,the judgement should be made by combine with the change of time domain and frequency domain characteristics.