巷道掘进过程煤岩破裂微震信号多参量监测研究

Research on multiparameter monitoring of microseismic signals of coal and rock rupture in tunnel excavation

为揭示深部矿井巷道掘进过程煤岩动力现象发生“前-中-后”的矿震显现规律,以潞安五阳煤矿巷道掘进为研究背景,利用ESG微震监测技术,对作业过程煤岩扰动及地应力变化引起的微震事件进行实时监测,并通过快速傅里叶变换(FFT)、小波包变换、S变换对作业过程中微震信号的时序、频谱和能量进行分析,构建微震多参量监测模型,得出如下结论:(1)监测期间发生微震事件的日累计频次及日累计频次变化率具有先上升后下降的趋势,主震发生当日出现日累计频次及变化率极大值;(2)一般事件、前兆事件和后震事件的微震信号振幅和能量均低于主震事件,但持续时间为主震信号的2~4倍,主震事件发生时,微震事件振幅达到峰值,信号频域向低频段移动;(3) 4类微震事件小波包能量整体呈现下降的趋势,第1频带和第16频带分别对应为极大值和极小值点,小波包频带能量以1~3频带为主,主震信号16频带能量所占百分比仍处于较高点,说明主震事件后期仍残存微震能量,工作面并不会马上进入安全期;(4)提出了微震多参量分析方法,构建了以时序S、时域T、频域F和小波包频带能量E为参数的4×4微震多参量监测模型,提高微震监测的准确性和可靠度.研究结果可为矿井煤岩动力灾害事故的预测和预警提供技术支持,为该类型矿井提前感知微震活动,及时响应预防措施提供理论依据.

In order to reveal the law of mine earthquake occurrence"pre-middle-post"the dynamic phenomenon of coal rock in the process of roadway excavation in deep mine.The microseismic monitoring technology is used to conduct real-time monitoring of microseismic events caused by operation disturbance and ground stress changes in the background of the excavation process of Wuyang Coal Mine in Lu'an.And through Fast Fourier Transform(FFT),Wavelet Packet Transform,and S-transform,to analyze the time series,spectrum,and energy of microseismic signals during the operation process,and a multi parameter monitoring model for microseismic signals is constructed.The following conclusion is drawn:(1)During the monitoring period,the daily cumulative frequency and rate of change of microseismic events have a trend of first increasing and then decreasing.The maximum daily cumulative frequency and rate of change occur on the day of the main earthquake;(2)The amplitude and energy of microseismic signals for general events,precursor events and aftershock events are lower than those of the main shock event,but their duration is 2~4 times that of the main shock signal.When the main shock event occurs,the amplitude of microseismic events reaches its peak,and the frequency domain of the signal moves towards the low-frequency band;(3)The overall energy of wavelet packets for 4 types of microseismic events shows a decreasing trend,with the 1st and 16th frequency bands corresponding to maximum and minimum points,respectively.The frequency band energy of wavelet packets is mainly in the 1~3 frequency bands,and the percentage of energy in the 16 frequency band of the main seismic signal is still at a high point,indicating that there is still residual microseismic energy in the later stage of the main seismic event,and the working face will not immediately enter the safety period;(4)A micro seismic multi parameter analysis method was proposed,and a 4×4 micro seismic multi parameter monitoring model was constructed with time series S,time domain T,frequency domain F,and wavelet packet frequency band energy E as parameters.It can improve the accuracy and reliability of microseismic monitoring.The research results can provide technical support for the prediction and early warning of coal and rock dynamic disasters in mines,and provide theoretical basis for early sensing of microseismic activity and timely response to preventive measures in this type of mine.