Research Into Extracting Methods For Dispersion Curve Of Rayleigh Wave

In order to make the geological structure beneath the ground surface clear,Rayleigh wave exploration method are used more and more in engineering projectsrecent years. The base of Rayleigh wave exploration is the frequency dispersion ofRayleigh wave, and the main task of the surface method is to get the dispersionfeatures of Rayleigh waves recorded on the ground surface in a construction site or onthe surface of a construction member. Whereas, the first thing we should do before theanalysis for the dispersion features of Rayleigh waves is to get reliable Rayleigh wavedata. To get Rayleigh-wave data, observe and reverse Ï„-p transforms are applied first on the recorded waveform data. These transforms can separate Rayleigh wave phase from the whole wave data, and the transforms is linear and reliable because of their good fidelity. In addition, the transforms can be easily realized with computer. Traditional Fourier transform is usually chosen to get the phase velocity of Rayleigh waves. But the Fourier transform is such kind of transform that analyzes a whole section of a wave lasting for a period of time, and can hardly reflect the characteristics of a certain time point somewhere in the wave. To overcome this shortcoming, wavelet analytical method, which can reveal the time and frequency features of waves at the same time, is adopted in this paper. At last, the frequency dispersion curves of Rayleigh waves both from actual project and from modeling are obtained in aid of the processing system developed with Ï„-p transforms and wavelet analysis. As contrast, the dispersion curves for the same data are also calculated by the processing method developed with traditional Fourier transform. The comparison between the two kinds of results shows that the processing system for surface wave developed with Ï„-p transforms and wavelet analysis is reliable better than the method developed with traditional Fourier transforms.