基于Burg功率谱的无砟轨道功能层缺陷边缘估计方法研究

高速铁路无砟轨道功能层缺陷直接影响高速铁路运营安全,而现有方法难以准确估计缺陷尺寸,造成无砟轨道状态评估困难。针对这一难题,该研究建立了带缺陷层状介质弹性波回波模型,分析了测点位置与功能层缺陷回波的关联关系,提出了弹性波缺陷边缘回波频率分布模式;研究了AR功率谱模型,分析了Burg功率谱的频率分辨率和相关参数获取方法,并在此基础上,提出了无砟轨道功能层缺陷边缘估计和缺陷成像方法;通过CRTSⅢ型无砟轨道现场试验对比分析,验证了该方法在无砟轨道缺陷检测中的适用性。研究结果表明:基于Burg功率谱方法能够较为准确地实现缺陷边缘估计和无砟轨道功能层缺陷成像。研究成果可用于高速铁路无砟轨道缺陷检测与状态分析,为高速铁路安全运营提供理论支撑。

Analysis on edge estimation of functional layer defect in ballastless track based on Burg power spectrum

Defects in the functional layer of ballastless track directly affect the operation safety of high-speed railway(HSR), but the existing methods are hard to accurately estimate the defect size, resulting in difficulties in state evaluation of ballastless track. To solve this problem, firstly, layered medium echo model of ballastless track with defect was established, the relationship between the location of the detection point and the defect echo of the functional layer was analyzed, and the frequency distribution model of the edge wave echo was proposed. Secondly, an autoregressive(AR) power spectrum model was studied, the frequency resolution of Burg power spectrum and the acquisition method of related parameters were analyzed, and on this basis, the imaging method of ballastless track functional layer defects was presented. Finally, CRTSⅢ ballastless track field experiment was carried out to verify the applicability of this method in defect detection of ballastless track. The results show that the imaging method based on Burg power spectrum can accurately perform the edge estimation and defect imaging of functional layer. The research results can be used for defect detection and state evaluation of ballastless track, and provide theoretical support for the safe operation of HSR.