Research On Micro-motion Detection Technology Of Cave In Dalian Bay

The micro-motion exploration method is based on the theory of stationary stochastic process.A geophysical method for obtaining stratigraphic information is obtained by extracting the dispersion curve from the acquired signal and inverting the dispersion curve.Compared to other traditional methods,the advantage of micro-motion exploration lies in its convenience,no need for observation environment,and the vibration generated by passing vehicles provides abundant high-frequency signal sources for micro-motion exploration,and because the noise is small,the extracted surface wave dispersion is small.The inversion of the inferred stratigraphic velocity from the inversion of the curve will have a higher resolution.Combined with the borehole data of the work area,the two-dimensional section of the underground structure can be accurately obtained.Surface waves are extremely sensitive to changes in the lateral velocity of the stratum.The detection of underground caves has the advantages of the method itself.This paper discusses the linear micro-motion acquisition method and data processing in a complex urban environment.According to the theory of micro-motion surface wave,the process of the dispersion curve equation was deduced and applied to the exploration of caves in Dalian Bay.The improved fast Knopoff algorithm was used to calculate the theoretical dispersion curve,and the influence of the changes of the shear wave velocity,longitudinal wave velocity,layer thickness,and density on the theoretical dispersion curve in the structural model was analyzed.In order to overcome the micro-motion exploration in the city affected by the topography using linear array mode.Linear array SPAC method,dispersion curve extraction method,and optimized genetic algorithm inversion method were applied to the study of cave exploration in Dalian Bay,and achieved good results.