| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 98 === Conventional SASW method is used fast Fourier transform to convert time domain signals to frequency domain. Then the frequency-dependent phase angle can be obtained from phase spectrum analysis. But it can be interfered with surrounding noise. This research will develop a time-frequency method to evaluate the velocity of surface wave. The method is used continuous wavelet transform to convert time domain signals to time-frequency domain signal. The velocity of surface wave will be determined from the incoming time of higher energy wave and the distance of two receivers. Because the signal has characteristics of time and frequency domain, the velocity can be expressed a function of frequency. Therefore, the dispersion curve will be evaluated from the analysis. The dispersion curves of a single layer soil, two layers soil and three layers soil are analyzed by the time-frequency meted. For practical application, a experimental test was performed to verify the rationality of the proposed method. From the results of numerical analysis and experiment test, it cam be concluded that the proposed method can evaluate the velocity of surface wave.
|
|---|
