基于HHT方法的混凝土桩无损检测

The Nondestructive Examination to Concrete Piles Based on the Theory of Hilbert-Huang Transform

由于混凝土桩基在工程中的广泛应用,其无损检测成为一个被广泛关注的课题。而传统的信号处理方式,如傅立叶变换、小波变换等,在处理非线性非稳态信号时存在着一定的不足。本文采用最新的希尔伯特-黄变换(HHT)方法对一个存在不良状况的混凝土桩和一个完整桩的测桩信号作了分析。并且利用边际谱对不同的不良状况引起的频率分布变化进行了探讨,比较了利用HHT方法对桩身不良状况进行定位的准确性,并进一步得出了当机械波通过不同种类的不良状况时,所得信号在HHT边际谱上所表现出的差异性。

Because of the widespread use of concrete piles in engineering filed, the study of the methods of concrete piles’ nondestructive examination has already become a research subject widely concerned. However, the traditional signal processing methods, such as Fourier Transform and Wavelet Transform, are somewhat defective in processing nonlinear signal or unstable signal. This paper used the latest signal processing method named as Hilbert-Huang Transform (HHT) to analyze detective signals of an integrity pile and a non-integrity pile. We verify the accuracy of defect location by HHT method. Furthermore, based on the theory of marginal spectrum, we also made a discussion about variation of frequency induced by different kinds of defects.