RESEARCH ON TIME-FREQUENCY ANALYSIS ALGORITHM AND INSTANTANEOUS FREQUENCY PRECURSORS FOR ACOUSTIC EMISSION DATA FROM ROCK FAILURE EXPERIMENT
GONG Yuxin1，HE Manchao2，3，WANG Zhenghong1，YIN Yuting1
(1. School of Mathematics and Statistics，South Central University for Nationalities，Wuhan，Hubei 430074，China；2. State Key Laboratory for Geomechanics and Deep Underground Engineering，China University of Mining and Technology，Beijing 100083，China；3. School of Mechanics and Civil Engineering，China University of Mining and Technology，Beijing 100083，China)
Abstract：In order to obtain the instantaneous frequency precursors containing such information as time，frequency，amplitude and dynamical information，which are the basis for rockburst prediction，wave-form based investigation on acoustic emission(AE) was carried out. Taking the uniaxially loaded granite specimen as a practical case，theoretical and computational analyses were conducted on the segmentation of the large AE data，theory and algorithm of the time-frequency transform and optimization of filtering performance for the analysis window functions. Such analytical or computational based outcomes were obtained as the formulas for assessment of temporal and spectral resolutions of the segmented data，principle for optimized segmentation of the large AE data，optimal design of window width and spectral parameters for the analysis window function，and establishment of the comprehensive optimal time-frequency analysis algorithm involving：(1) the optimal segmentation of the large AE data；(2) optimal design of the analysis window function；(3) locating the dominant frequency band using short-time Fourier transform(STFT)；(4) determining exactly the central frequencies for the dominant frequency band using Wigner-Ville distribution(WVD)，and enhancement of the time-frequency contour graphs for a detailed representation of the dynamical information. Results from application of the proposed algorithm in analysis of the case demonstrate that the segmented data sets match well with the dynamical process at which fractures propagate at specific stress level；the increase in frequency localization performance and reduction of spectral leaks；good ability in accurately determining central frequency of the dominant frequency band obtained by STFT and avoiding identification of the“cross terms”in WVD. The instantaneous frequency precursors containing the dynamical information can better describe the precursory information for nonlinear process of the rock failure and provide a new，robust means for rock failure prediction and mechanism comprehension.
宫宇新1，何满潮2，3，汪政红1，尹雨婷1. 岩石破坏声发射时频分析算法与瞬时频率前兆研究[J]. 岩石力学与工程学报, 2013, 32(4): 787-799.
GONG Yuxin1，HE Manchao2，3，WANG Zhenghong1，YIN Yuting1. RESEARCH ON TIME-FREQUENCY ANALYSIS ALGORITHM AND INSTANTANEOUS FREQUENCY PRECURSORS FOR ACOUSTIC EMISSION DATA FROM ROCK FAILURE EXPERIMENT. , 2013, 32(4): 787-799.
[1] HE M C，MIAO J L，FENG J L. Rock burst process of limestone and its acoustic emission characteristics under true-triaxial unloading conditions[J]. International Journal of Rock Mechanics and Mining Sciences，2010，47(2)：286–298.
[2] 钱七虎，何满潮. 岩爆机制探索(前言)[M]. 北京：中国科学技术出版社，2011：1–22.(QIAN Qihu，HE Manchao. Exploring into rockburst mechanisms(forward)[M]. Beijing：China Science and Technology Press，2011：1–22.(in Chinese))
[3] 施克仁. 无损检测新技术[M]. 北京：清华大学出版社，2007：53–106.(SHI Keren. New technology of nondestructive testing[M]. Beijing：Tsinghua University Press，2007：53–106.(in Chinese))
[4] 李庶林，尹贤刚，王泳嘉，等. 单轴受压岩石破坏全过程声发射特征研究[J]. 岩石力学与工程学报，2004，23(15)：2 499–2 053.(LI Shulin，YIN Xiangang，WANG Yongjia，et al. Studies on acoustic emission characteristics of uniaxial compressive rock failure[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(15)：2 499–2 053.(in Chinese))
[5] 唐春安，乔 河，徐小荷，等. 矿柱破坏过程及其声发射规律的数值模拟[J]. 煤炭学报，1999，24(3)：266–269.(TANG Chun?an，QIAO He，XU Xiaohe，et al. Numerical simulation on pillar failure and associated acoustic emissions[J]. Journal of China Coal Society，1999，24(3)：266–269.(in Chinese))
[6] 何满潮，苗金丽，李德建，等. 深部花岗岩试样岩爆过程实验研究[J]. 岩石力学与工程学报，2007，26(5)：865–876.(HE Manchao，MIAO Jinli，LI Dejian，et al. Experimental study on rockburst processes of granite specimen at great depth[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(5)：865–876.(in Chinese))
[7] ISHIDA T，KANAGAWA T，KANAORI Y. Source distribution of acoustic emissions during an in-situ shear test：implications for an analog model of seismogenic faulting in an inhomogeneous rock mass[J]. Engineering Geology，2010，110(3/4 )：66–76.
[8] LI Y H，LIU J P，ZHAO X D，et al. Experimental studies of the change of spatial correlation length of acoustic emission events during rock fracture process[J]. International Journal of Rock Mechanics and Mining Sciences，2010，47(8)：1 254–1 262.
[9] 李小军，路广奇，李化敏. 基于声发射事件b值变化规律的岩石破坏前兆识别及其局限性[J]. 河南理工大学学报：自然科学版，2010，29(5)：663–666.(LI Xiaojun，LU Guangqi，LI Huamin. Identification of the predictive information of rockmass failure based on the law of b-value change of acoustic emission events and its deficiency[J]. Journal of Henan Polytechnic University：Natural Science，2010，29(5)：663–666.(in Chinese))
[10] 杨 健，王连俊. 岩爆机制声发射试验研究[J]. 岩石力学与工程学报，2005，24(20)：3 796–3 802.(YANG Jian，WANG Lianjun. Study on mechanism of rock burst by acoustic emission testing[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(20)：3 796– 3 802.(in Chinese))
[11] 杨永杰，陈绍杰，韩国栋. 煤岩压缩破坏过程的声发射试验[J]. 煤炭学报，2006，31(5)：562–565.(YANG Yongjie，CHEN Shaojie，HAN Guodong. Experiments on acoustic emission during compression rupture procedure of coal sample[J]. Journal of China Coal Society，2006，31(5)：562–565.(in Chinese))
[12] 何满潮，钱七虎. 深部岩土力学基础[M]. 北京：科学出版社，2010：1–30.(HE Manchao，QIAN Qihu. Foundation of rock and soil mechanics in depth[M]. Beijing：Science Press，2010：1–30.(in Chinese))
[13] XU X F，DOU L M，LU C P，et al. Frequency spectrum analysis of micro-seismic signal of rock bursts induced by dynamic disturbance[J]. Mining Science and Technology，2010，20(5)：682–685.
[14] LIU C P，DOU L M，LIU B，et al. Microseismic low-frequency precursor effect of bursting failure of coal and rock[J]. Journal of Applied Geophysics，2012，79(4)：55–63.
[15] LU C P，DOU L M，LIU H，et al. Case study on microseismic effect of coal and gas outburst process[J]. International Journal of Rock Mechanics and Mining Sciences，2012，49(1)：101–110.
[16] FIJII Y，ISHJIMA Y，DEGUCHI G. Prediction of coal face rockbursts and microseismicity in deep longwall coal mining[J]. International Journal of Rock Mechanics and Mining Sciences，1997，34(1)：85–96.
[17] NEILD S A，MCFADDEN P D，WILLIAMS M S. A review of time-frequency methods for structural vibration analysis[J]. Engineering Structure，2003，25(6)：713–728.
[18] COHEN L，GALLEANI L，HEDGES R，et al. Time-frequency analysis of a variable stiffness model for fault development[J]. Digital Signal Processing，2002，12(2/3)：429–440.
[19] NI Q Q，IWAMOTO M. Wavelet transform of acoustic emission signals in failure of model composites[J]. Engineering Fracture Mechanics，2002，69(6)：717–728.
[20] 逄焕东，张兴民，姜福兴. 岩石类材料声发射事件的波谱分析[J]. 煤炭学报，2004，29(5)：540–544.(PANG Huandong，ZHANG Xingmin，JIANG Fuxing. The spectrum analysis of acoustic emission signal in rock materials[J]. Journal of China Coal Society，2004，29(5)：540–544.(in Chinese))
[21] 苗金丽，何满潮，李德建，等. 花岗岩应变岩爆声发射特征及微观断裂机制[J]. 岩石力学与工程学报，2009，28(8)：1 593–1 603. (MIAO Jinli，HE Manchao，LI Dejan，et al. Acoustic emission characteristics of granite under strain rockburst test and its micro- fracture mechanism[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(8)：1 593–1 603.(in Chinese))
[22] BENSON P M，VINCIGUERRA S，MEREDITH P G.，et al. Spatial- temporal evolution of volcano seismicity：a laboratory study[J]. Earth and Planetary Science Letters，2010，297(1/3)：315–323.
[23] HARDY H R. Theory and application of acoustic emission/microseismic techniques[M]. Clausthal，Germany：Trans. Tech. Publications，1985：110–157.
[24] BRACEWELL R N.. The Fourier transform and its applications[M]. 3rd ed. Singapore：McGraw-Hill Book Co.，2000：21–87.
[25] 谢和平，陈忠辉. 岩石力学[M]. 北京：科学出版社，2004：7–14.(XIE Heping，CHEN Zhonghui. Rock mechanics[M]. Beijing：Science Press，2004：7–14.(in Chinese))
[26] COHEN L. Time-frequency analysis[M]. NJ：Prentice Hall，Englewood Cliffs，1995：69–83.
[27] COHEN L. Time-frequency distributions：a review[C]// Proceedings of IEEE International Conference. [S.l.]：[s.n.]，1989：941–979.
[28] CHAN H L，LIN J L，DU C C， et al. Time-frequency distribution of heart rate variability below 0.05 Hz by Wigner-Ville spectral analysis in congestive heart failure patients[J]. Medical Engineering Physics，1997，19(6)：581–587.
[29] INGLE V K，PROKIS J G. 数字信号处理(Matlab版)[M]. 刘树堂译. 西安：西安交通大学出版社，2008：203–246.( INGLE V K，PROKIS J G. Digital signal processing[M]. Translated by LIU Shutang. Xi?an：Xi?an Jiaotong University Press，2008：203–206.(in Chinese))
[30] CAI M，KAISER P K，MORIOKA H，et al. FLAC/PFC coupled numerical simulation of AE in large-scale underground excavations[J]. International Journal of Rock Mechanics and Mining Sciences，2007，44(4)：550–564.
[31] SHIOTANI T，OHSTU M，IKEDA K. Detection and evaluation of AE waves due to rock deformation[J]. Construction Building Materials，2001，15(5/6)：235–246.
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