This research aims to detect cement grouting defects in corrugated pipes using the ultrasonic impact-echo method. A combined signal processing technique that included de-convolution technique, information entropy and cross-correlation were proposed to identify and characterize defects. Several numerical models were constructed to simulate and analyze the results using the finite element method. The stripping size of the defects in the corrugated pipe was recognized by analyzing the information entropy and correlation coefficients of the echo signals. Experiments were carried out on a concrete specimen containing artificial defects with varying stripping sizes and numbers of elements. The experimental results were consistent with the simulated predictions. .
