矿山微震信号多层联合降噪研究

Study on multi-layer joint noise reduction of mine microseismic signal

目的:矿山工作环境复杂,干扰噪声多,微震信号和噪声混叠在一起,对微震信号分析产生干扰,影响后续震相到时拾取与震源定位的工作,需对微震信号进行降噪研究。方法:针对微震信号的随机性和非平稳性,本文提出了一种基于多层联合的信号降噪方法,将SVD(奇异值分解)作为第一层降噪方法,去除信号中的白噪声;EMD(经验模态分解)作为第二层降噪方法,处理随机、非平稳的微震信号;小波阈值作为第三层降噪方法,消除EMD产生的模态混叠现象。结果:经过实验分析表明本文方法对不同信噪比的仿真信号和实际微震信号都有很好的降噪效果。结论:克服了单一降噪方法降噪效果不好的缺点,能极大提高信号信噪比,并且和原信号的相似度高,为微震信号降噪提供了一种新思路。

Purpose:The working environment of the mine is complex,and there are many interference noises.Microseismic signals and noises are mixed together,which interferes with the analysis of microseismic signals and affects the subsequent work of phase arrival picking and source location.Therefore,it is necessary to study the noise reduction of microseismic signals.Method:In view of the randomness and non-stationarity of microseismic signals,a signal denoising method based on the multi-layer joint is proposed in this paper.SVD(singular value decomposition)is used as the first layer denoising method to remove the white noise in the signal.EMD(Empirical Mode Decomposition)is used as the second layer noise reduction method to deal with random and non-stationary microseismic signals.As the third layer noise reduction method,the wavelet threshold eliminates the modal aliasing phenomenon generated by EMD.Result:The experimental analysis shows that the proposed method has a good noise reduction effect on the simulation signal and the actual microseismic signal with different signal-to-noise ratios.Conclusion:It overcomes the disadvantage of the poor noise reduction effect of a single noise reduction method,can greatly improve the signal-to-noise ratio of the signal,and has a high similarity with the original signal,which provides a new idea for microseismic signal noise reduction.