Applications of spline wavelets for pile integrity testing
WU Min-zhe · Journal of Xi'an University of Architecture & Technology · 2004
Pile integrity testing method ,a low strain method for pile integrity testing ,is now widely employed in construction fields.So,the results of the tests must also be accurately evaluated. Now,the interpretations of the pile top velocity traces in time domain is a simple visual inspection of the data by an experienced engineer intuitively and the method is too simplified and can not make full use of the inherent content of the recorders, especially when the recorders are polluted by noises.The noise is usually composed of ambient noise ,electric noise and resistance created by soils around the shaft.The difference between the useful component and the noise of the signal lies in the time-frequent characteristic. The signal are decomposed in the time～frequent domain by use of the spline waveletd of order and, the different type of noise can be differentiated.So, by setting the coefficient of specific time and frequence band to zero, the reconstruction signal can remove the unwaned signal component. It can greatly improve the effect of interpretation about pile integrity testing.