基于矢量波数变换法的主动源瑞雷波多模式提取方法在近地表地层结构探测中的应用研究

Based on the array of the transient multi-channel analysis of surface waves (MASW), Rayleigh wave dispersion imaging methods including vector wavenumber transformation method (VWTM), phase shift, and high-resolution linear Radon transform are used to carry out comparative analysis. First, the dispersion imaging results of synthetic data are compared to analyze the quality of the three methods. The VWTM is found superior to the other two in terms of resolution, accuracy of higher modes, fitting degree with theoretical dispersion curves and anti-noise property. In the actual Rayleigh wave detection, the VWTM can still has advantages in foundamental mode imaging accuracy and higher order modes imaging quality. Then the genetic algorithm is employed to invert the dispersion curves of fundamental mode and higher modes. The result is more accurate and stable when higher modes are combined in the inversion, it also performs much better in reducing non-uniqueness of inversion. The research shows that the VWTM can extract multi-mode characteristics of Rayleigh wave dispersion effectively and with high quality in field prospecting, which provides a reliable data foundation for joint inversion of multi-mode of Rayleigh wave dispersion curves. In conclusion, the VWTM combined with effective inversion method can remarkably improve the accuracy of near surface stratigraphic structure detection and has great potential in enhancing Rayleigh wave exploration capability.