Research On Local Scale Region Microseism Location Based On High Density Stations

Coal is an important energy in China,with the deep development of coal mining in recent years,occurrence of disasters in which mine earthquake is the most typical are serious threat to the coal mine safety.As an effective means of monitoring and early warning of mine earthquake,there has been a problem that microseismic monitoring location effect is not ideal,so this paper choose high density stations microseismic monitoring in local scale region,in order to help to improve the positioning accuracy.In the paper,based on a gold mine with good geological structure in Fuxin and super high frequency and multiple channels mine seismic structure monitor,seismic signals are collected by high density stations in several hundred meters scale.Test the rock P wave velocity in the moist state by means of ultrasonic.Use fast Fourier transformation(FFT),wavelet time-frequency analysis and wavelet packet energy characteristic analysis method to analyze the characteristics of mine earthquake and gold mine micro blasting signals.The central frequency of them are about 33.5Hz and 1380 Hz respectively,the energy are mainly concentrated in 0~20Hz and 0~500Hz respectively.The frequency of mine earthquake signal changes with time in the form of low frequency,high frequency and low frequency,blasting signal mainly changes from high frequency to low frequency.Use the wavelet analysis theory to the signals de-noising,picking up the onset time,using PSO algorithm in known and unknown velocity to locate micro blasting sources.Analyzing the influence of location method,velocity error,source position on source location by a model,found that source position affects location accuracy,location accuracy of sources in sensors envelope region is significantly higher than that outside the region;compared with the known velocity location,the unknown velocity location has better adaptability and location results are relatively stable;when velocity error existing,location accuracy of the known velocity is more and more poor with velocity error increasing,the farther distance from monitoring regional center,the more obvious this phenomenon will be.The influence of stations density on the location is analyzed by means of locating two micro blasting seismic sources.Influence of station density on location is analyzed from two aspects: number of sensor plane and sensors,and proves that developing high density stations of microseismic monitoring is an effective way to improve the location accuracy in mining area.Analysis shows that number of sensors has a negative exponential relationship between location error and station number.The results of this research can provide some theoretical reference value and practical guidance for mine microseismic monitoring.