Using continuous wavelet transform to construct the dispersion image for soil layers

This study used a time-frequency domain analysis for estimating the dispersion curve of a Rayleigh wave by using two receivers. The signals were first transformed using continuous wavelet transform. A similar slant stack procedure was used to analyze the wavelet transform signals and extract a dispersion image. This method is advantageous because it requires no empirical judgment in phase unwrapping and few receivers. To examine the applicability of the method for evaluating the dispersion curve for soil layers with lateral heterogeneity, three synthetic examples and an experience example were investigated. In these examples, numerical simulations of the surface wave seismic test were performed using the finite difference FLAC code. The results revealed that the estimates of the surface wave dispersion curve, obtained using the method, coincide with those of the theoretical values. A high-resolution dispersion image is generated by increasing the spacing of receivers. The method is applicable for extracting a dispersion image for lateral heterogeneous soil layers.