声发射梅尔倒谱系数在砂岩破裂分析的应用  

Applying Mel-frequency cepstral coefficient of acoustic emission for analyzingfracture and failure of sandstone specimens

作　　者：李振雷 李娜 杨菲 宋大钊 何学秋 薛雅荣 王洪磊[1] 殷山 LI Zhenlei;LI Na;YANG Fei;SONG Dazhao;HE Xueqiu;XUE Yarong;WANG Honglei;YIN Shan(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083 [2]北京科技大学金属矿山高效开采与安全教育部重点实验室,北京100083

出　　处：《煤炭学报》2023年第2期714-729,共16页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(51904019,52011530037)。

摘　　要：声发射技术在煤岩破裂分析领域进行了大量应用,取得了诸多有益成果,对煤岩动力灾害监测预警提供了重要指导,然而煤岩声发射分析仍存在进一步研究和完善的空间,亟待提出新的声发射分析方法。为此,开展了预制裂纹砂岩试样单轴加载破坏实验,同步采集了加载全程的应力应变数据和全波形声发射数据,并对试样进行全程高清摄像;利用声波分析手段提取了砂岩的声发射梅尔倒谱系数,探讨了该系数在砂岩破裂分析的优势及其原因,分析了该系数对砂岩破坏过程的响应,由此进一步研究揭示了预制裂纹砂岩试样的破裂破坏演化特征及声发射梅尔倒谱系数前兆信息。结果表明:对同种砂岩的不同试样,由不同通道采集的声发射信号提取的同号梅尔倒谱系数的变化特征相似、变化量相近、偏差程度小(5%~15%),并且在砂岩加载全程具有阶段性和敏感性的变化特征,说明声发射梅尔倒谱系数具有稳定性优势,可作为反映砂岩破裂状态的特征参数;梅尔倒谱系数可对声发射波形进行很好表征,系数提取过程不对波形设置门槛值,系数值由一段时间内声发射波形幅度和密集程度等整体形态决定,而不同通道采集的声发射波形整体形态在一段时间内趋向于相似,是该系数具有稳定性优势的原因;在砂岩破坏阶段,梅尔倒谱系数呈现周期性升降波动,对应应力曲线的周期性降升和高幅度声发射波形的间断性产生,3者的变化量之间具有显著的正相关关系,说明该系数的波动性及其强弱可反映砂岩的破裂过程及破裂的剧烈程度,是砂岩破裂的响应,由此揭示了砂岩的间歇性破裂破坏演化特征,该特征随着临近砂岩失稳破坏而变得愈发剧烈;以此为指导,利用梅尔倒谱系数周期性波动的波峰与波谷之差(即波动差)来表征系数的波动性强弱并描述砂岩间歇性破裂的剧烈程度,得到了梅尔倒�Acoustic emission(AE)technology has been applied in the field of coal rock fracture analysis,and many beneficial results have been achieved,which provides important guidance for coal rock dynamic hazard monitoring and early warning.However,there is still a need for further research and improvement in the area of coal rock fracture analysis using AE,e.g.novel AE analysis method.Therefore,this study conducted uniaxial compressive loading experiments on sandstone specimens with prefabricated cracks.Meanwhile,the stress-strain data,full-waveform AE data and high-resolution photographs of the specimens were collected simultaneously in the whole loading process.Mel-frequency Cepstral Coefficient(MFCC)was extracted from AE signal in the whole loading process of sandstones by utilizing sound wave analysis means.The advantages of applying MFCC of AE to analyzing sandstone fracture and its underlying mechanism were discussed.The response law of MFCC in the failure process of sandstone was investigated.On this basis,the fracture and failure evolution characteristics of sandstone specimens with prefabricated cracks were revealed,and the MFCC precursors of sandstone failure were obtained.Results show that the evolution characteristics are similar,the variation is close,and the deviations of the variation are small(i.e.from 5%to 15%)even if the MFCCs were extracted from AE signals that were collected by different AE channels and from different specimens.In addition,the MFCCs of AE behave sensitively in the whole loading stage.This indicates that the MFCCs of AE have the advantage of stability and can be used as a characteristic parameter for characterizing the fracture of sandstone.It is found that the MFCCs are obtained without setting a threshold to AE waveform,and its value is determined by the overall shape of AE waveform over a certain period of time including the amplitude,density,and intervals among adjacent AE signals etc.In addition,the overall shape of AE waveform collected by different channels is quite similar.Thus

关 键 词：动力灾害 监测预警 砂岩破坏 声发射 梅尔倒谱系数 特征提取 前兆信息 

分 类 号：TD76[矿业工程—矿井通风与安全]