Study On Automatic Identification And Source Location Method Of Double Seismic Phases In Microseismic Signal

In the process of deep mining,dynamic disasters such as rock burst and Goaf Collapse often occur.As a common monitoring method,microseismic monitoring can predict and monitor the failure of rock stratum interface and the fracture of matrix or inclusions in the mining process,so as to ensure the construction safety.The key to the inversion accuracy of source location and earthquake occurrence time lies in the effectiveness of microseismic phase identification method and the accuracy of source location method composed of arrival-time picking method and optimization algorithm.In order to realize automatic and efficient identification of microseismic events and high-precision source location,this paper studies microseismic phase identification,arrival-time picking,optimization algorithm and source location by means of theoretical analysis,algorithm programming,indoor test,numerical calculation and engineering verification,and puts forward the adaptive wheel-motion classification method(AWC method),the time-frequency analysis-downhill comparison method(TFA-DC method),the variable step accelerated search method(VSAS method)and the TFA-DC-double seismic phases location method(TD-DL method).The main results are as follows:(1)Compared with the improved STA/LTA method,the AWC method has higher fault tolerance and stability for the identification of signals with different lengths.Under the model test,the identification accuracy of the AWC method is improved by 25.0%,the identification deviation standard deviation is 17.4% of the former,and the average of calculation time and standard deviation are 44.2% and 67.4% of the former respectively,under the practical engineering,the identification accuracy of the AWC method is improved by 4.8%,the identification deviation standard deviation is 34.2% of the former,and the average of calculation time and standard deviation are 40.9% and 55.9% of the former respectively.(2)TFA-DC method is compared with the improved STA/LTA method.The former can pick the accurate arrival-time of P-wave and the peak arrival-time of S-wave at the same time,while the latter can only pick the accurate arrival-time of P-wave.The average time difference and standard deviation of P-wave of the former are 6.18‰ and 3.98‰ of the latter respectively.The average calculation time and standard deviation of single arrival-time picking of the former are 43.99% and 10.54% of the latter respectively.The failure rate of arrival-time picking of the former is 0 and that of the latter is 15.63%.(3)In the simulation example,compared with the simulated annealing algorithm and the genetic algorithm,the standard deviation of target function value,location error and wave velocity error of the VSAS method are all 0;The average location error of the VSAS method is0.7% and 1.9% of the other two;The average calculation time of the VSAS method is 6.9% and33.2% of the other two.The influence of changing each parameter on the location error is between 0.005 m and 0.025 m;Reducing the lower limit of search step size can effectively improve the accuracy of the location results and increase the corresponding calculation time.(4)Due to the increase of constraint information of S-wave arrival-time and the trend of minimum value of objective function,the TD-DL method improves the integration ability of known information such as geophone coordinates and arrival-time of double seismic phases,and makes the location results tend to the one with smaller location error in two kinds of single seismic phase location results.Using the migration relationship between the arrival-time of P-wave and S-wave picked by the TFA-DC method,the TD-DL method offsets the location error calculated by P-wave and S-wave single seismic phase to a certain extent,so as to improve the accuracy of source inversion location;Under the model test,the average location error of the TD-DL method is 23.9% and 18.9% of P-wave and S-wave single seismic phase location respectively,and the standard deviation of location error is 50.9% and 36.9% of P-wave and S-wave respectively.Under the engineering data,the average location error of the TD-DL method is 8.1% and 12.6% of P-wave and S-wave single seismic phase location respectively.This paper has 53 figure,29 table and 60 reference.