Laminar Imaging Study Of Wave Velocity Field For Surface Microseismic Monitoring In Mines

Microseismic is an important technical tool for mine monitoring and disaster prediction and early warning,and has been widely used in impact ground pressure mines.Due to the limitations of underground microseismic monitoring arrangement layer,space and mode,the surface microseismic monitoring system has been developed more rapidly in recent years.In this paper,based on ground microseismic monitoring,the research on wave velocity field laminar imaging for ground microseismic monitoring in mines is carried out by combining theoretical analysis,experimental research and engineering application from the microseismic waveform automatic pickup algorithm,ground microseismic station arrangement optimization and microseismic positioning technology,which affect the accuracy of wave velocity field laminar imaging.The following aspects were mainly carried out:In the research of microseismic waveform automatic pickup algorithm,an automatic waveform pickup method is proposed,which is based on the long and short time window technology,and the automatic pickup accuracy is improved by the introduction of feature functions and the adjustment of relevant parameters such as long time window,short time window,ratio function value and gradient value.The program is written using matlab software,and the method is tested and verified by experiments to achieve automatic waveform and noise pickup.In the research of microseismic station arrangement optimization method,a noise index-based ground station arrangement optimization method is proposed,which is based on the noise data collected by the station,and the mutual correlation and Green’s function calculation of station noise are carried out and dispersion curves are obtained through noise pre-processing techniques.A program is written to realize the noise index for station layout optimization.In the research of microseismic localization technology,a global search and local optimization seeking microseismic localization algorithm is proposed,and the objective function of the search is constructed through the localization theory,and the influencing factors of microseismic localization accuracy such as the number of sensors and spatial distribution,wave velocity non-uniformity,and grid size are analyzed.The program of global search and local search optimization microseismic localization algorithm is prepared,and the accuracy of global search and local search optimization microseismic localization algorithm is tested through laboratory lead break experiments,field blast seismic source localization method and comparative analysis with other microseismic localization methods.In the research of wave velocity laminar imaging,from the basic principle of laminar imaging,the active laminar imaging program based on blast seismic source,the passive laminar imaging program based on microseismic source and the noise laminar imaging program based on noise data were prepared and tested for the wave velocity laminar imaging algorithm in view of the different site conditions and the demand for laminar imaging technology in mines.In terms of engineering applications,the automatic waveform pickup,station arrangement optimization,microseismic localization and laminar imaging techniques studied in this paper are used in a mine as an engineering background for preliminary engineering practice and application,providing references for monitoring,prediction and early warning of mine impact ground pressure hazards.