Wavelet analyses for stress wave detection of piles

Non-destructive detection by using stress wave plays an important role in ensuring safety of structures in civil engineering. At the present time, sonic pulse echo method, i.e. low strain method, is widely used in pile integrity detection. In principle, pile integrity detection is an inverse problem of wave propagation1]. Note that two boundary conditions are required in solving a direct problem of wave propagation. Since only the particle velocity at a pile top is measured in practical pile …

Wavelet analyses for stress wave detection of piles

The theoretical foundation for application of wavelet analysis to pile integrity detection has been presented. The mechanism of spectral variations of reflected pulse from various defects in piles is explained by using the wave scattering theory. The theoretical analyses have been verified through the tests of model piles and a lot of engineering piles. A quantitative evaluation method for estimating damage degree of piles is proposed. The characteristic indexes describing spectrum variations of reflected signals and their critical values are given. They can be used not only to evaluate the damage degree but also to identify the kinds of pile defects.