ANALYSIS OF DISPERSED MULTIMODE SIGNALS OF THE SASW METHOD USING THE MULTIPLE FILTER CROSS-CORRELATION TECHNIQUE

Spectral analysis of surface waves (SASW) is a nondestructive in-situ testing method used for determining the thickness and elastic properties of pavement and soil sites using the dispersion characteristics of surface waves. In previous studies, it has been demonstrated that for some sites errors may arise in experimental dispersion curves when the usual SASW test and data analysis procedures are followed, in particular the phase unwrapping procedure and source-to-near-receiver spacing distance. These errors occur due to the participation of more than one surface wave mode in SASW signals. In this study, the multiple filter/crosscorrelation technique often used in earthquake seismology for the analysis of multi-mode earthquake records is presented and applied for calculating phase velocities from SASW signals. It is demonstrated that this technique produces results that are generally more accurate than those produced by the usual phase unwrapping procedure.