Wavelet Analysis And Its Application In Integrity Testing Of Piles

By means of theoretical and experimental study, synthetic methods combing numerical simulation and in-situ test are applied to explore signals of in-situ test from model and actual piles, and computer simulation about dynamic test of piles with wavelet analysis in present paper. Meanwhile, popular manual neural network technique is adopted, and at last the computer simulation and actual signal analysis results show that this approach can be used to precisely diagnose the faults of piles. Following conclusions are drawn:(1) Based on the one-dimension stress wave theory, the propagating process and reflection characteristics of stress wave under impulsed load in concrete piles are studied by dynamic finite element method. The spatial surface of velocity time history about the transverse vibration of a entire pile is shown in a three-dimensional mesh figure. The validity of this manner is verified through comparison of the simulated curves and the measured curves. Consequently, the models, the parameters of pile-soil interaction and the results of numerical simulation in this paper are proved to be correct and it will play an important role in increasing the accuracy of dynamic test of pile integrity.(2) The present paper puts forward the object of studies on signals of dynamic test about piles with wavelet analysis. The traditional testing data of stress wave reflection is exploited. More available information, which expresses the propagating process of stress wave in piles, is obtained by getting ride of errors from actual measured signals. The conduction results, with some examples shown, demonstrate that this method can get more accuracy and flexibility.(3) Wavelet transform has a good localization character both in time-domain and frequency-domain, and neural network has a good property of nonlinear mapping. Therefore, an analytic method of dynamic testing signals combing with advantages of...