| At present,the existing mines in China have gradually entered deep mining,and the frequency and number of mine earthquakes will be further improved,and the disaster is becoming more and more serious.Microseismic monitoring technology has been proved to be an effective means of monitoring the occurrence of mine earthquakes.In this paper,aiming at the random dispersion and system deviation of microseismic source location,the method of combining theoretical analysis,mathematical derivation and field test data verification is used to further improve the microseismic data processing method,explore the optimization and improvement of source location theory,improve the inversion accuracy of source location and ensure the safety of mine production.The random positioning dispersion is generated by the first arrival time error of P wave.In order to achieve the accurate pick-up of the first arrival time of P wave,the propagation and motion of P wave of microseismic are studied by combining linear elastic dynamics,field theory and ray theory,and the geometric analytical properties of the source are explored.The travel time and ray path of P wave from the source point to the geophone of microseismic monitoring station are tracked by using the test ray method,and the calculation methods of P wave travel time and epicentral distance are given.Secondly,the self-defined signal-noise index is used as the determination condition,and the channel data with high quality and suitable for QONSL method to pick up preference are selected as the input to improve the accuracy of P wave arrival;for the three-dimensional microseismic signal seriously polluted by noise,the weight distribution of each channel data is unequally superposed according to the signal-noise index.Different detection functions are constructed to comprehensively pick up the first arrival time of P wave,and the random dispersion of source location is reduced by reducing the picking error of P wave.The systematic positioning deviation is mainly caused by the P wave velocity and the solution of the time residual value.In this paper,a combined positioning method is formed based on the linear equation positioning method and the improved Geiger positioning method,and the measurement method of P wave velocity structure and the approximate velocity model are introduced.The singular value decomposition,centralization and calibration techniques for solving the time residual can greatly reduce the condition number of the coefficient matrix of the equations,and solve the problem of positioning divergence caused by matrix singularity.The correction method of the initial equation and the estimation method of the source parameters are proposed,which avoids the problem that the time residual function converges to the local minimum or even cannot be located,and reduces the systematic deviation of the source location.The joint location method was tested using the blasting test data of the Shizhuyuan Mine.Compared with the existing methods,the optimal positioning error of the joint location method was 4.49 m.The QONSL method and joint location method are verified by the microseismic monitoring data of Wulong Mine in Fuxin City and Hongyang No.3 Mine in Shenyang City,respectively.The QONSL method has the ability of independent selection of signal channels.Compared with STA/LTA algorithm,the picking accuracy of the P wave in the QONSL algorithm is improved by 72%,and the fluctuation of the overall error range is reduced by 75%.The QONSL method is used to automatically pick up the first arrival time of the P wave instead of the artificial observation time of the microseismic monitoring system.Compared with the results of the ground microseismic monitoring system,the positioning results using the joint location method are more reliable.This paper has 61 figures,16 tables,and 110 references. |
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