Abstract: “Nonlinear amplification of velocity signals in lowstrain integrity tests is typically done in order to enhance weak echoes and to superimpose any peak reflections. However, unraveling hidden information within signals obscured by noise may sometimes fail when using the conventional method. Therefore, a pile defect identification system is presented in this study based on nonlinear amplification and wavelet packet transform (WPT). After the conventional nonlinear amplification method is applied, the signals are decomposed by WPT in which the detection of the feature parameters from the presence of any geometric or material defects may easily be identified. To serve as a guide in the interpretation of the various characteristics of peak wave forms that are associated with defects, diagnostic rules are presented in this study. In addition, a parametric study was performed using the finite element method and results have shown that the identification method based on WPT can be a useful too”

Keywords: diagnostic rule, pile defects, wavelet packet transform, nonlinear amplification method