Research On Surface Wave Dispersion Curve Extraction Based On Radon Transform

In the process of surface wave propagation,it carries a lot of geological information.Through the practical application in the field of engineering exploration,it is found that the surface wave exploration is convenient and fast,low cost,suitable for various sites and high resolution.Surface wave exploration has become an important means of engineering geological exploration,which has great influence on the field of engineering geological exploration.According to the different source surface wave exploration can be divided into artificial source surface wave exploration and natural source surface wave exploration.No matter what kind of surface wave exploration method is adopted,it is to transform the collected surface wave records from the space and time domain to the frequency and velocity domain,and extract the surface wave dispersion curve for inversion interpretation.Therefore,the extraction of surface wave dispersion curve is the most critical step in the process of surface wave exploration.Multi-channel transient surface wave exploration method is the most commonly used surface wave exploration method.The main dispersion curve extraction methods include f-k method,phase shift method and Radon transform method.In this paper,the principle of surface wave dispersion curve extraction by Radon transform is studied,and the surface wave dispersion curve extraction program based on Radon transform is constructed.Through the establishment of geological model,the full-wave field numerical simulation was used to synthesize the surface wave records of geological models with different layers,and the algorithm program was used to process the surface wave records.The processing results were compared with the theoretical results of forward modeling and the extraction results of f-k method,respectively,and the correctness of the algorithm program was verified.The constructed algorithm program was used to process the surface wave records with different channel spacing.The processing results were compared with the f-k method,and it was found that the algorithm program had better suppression effect on spatial spurious frequency than the f-k method.F-k method can only extract dispersion information in a certain frequency range,and the algorithm program can extract dispersion information in higher frequency band.F-k method can extract the dispersion information in the low frequency band,but the algorithm program cannot extract the dispersion information in the lower frequency range.Field surface wave records were collected and processed with the algorithm and program constructed.The processing results were compared with the f-k method to verify the field applicability of the algorithm and program.By comparing the processing results of the equal-trace interval surface wave record with those of the variable-trace interval surface wave record,it is verified that the algorithm program has a good processing effect on the variable-trace interval surface wave record,while the f-k method requires that the sampling interval in the space and time domain must be equally spaced,otherwise it will greatly affect the extraction accuracy of dispersion curve.