不同高度花岗岩岩爆试验的声发射特征
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摘要
岩石尺寸是影响其力学行为的重要因素,而岩爆是岩石处于复杂应力状态下的特殊力学响应,因此研究岩爆过程中的尺寸效应影响问题具有重要意义。利用室内改进的真三轴仪(简称MTTA)岩爆模拟试验系统和美国物理声学公司(简称PAC)声发射(AE)监测系统,对具有不同高度的花岗岩进行室内岩爆模拟试验,观察岩石试件破坏特征,分析花岗岩试件岩爆过程中声发射信号的参数特征、波形频谱特征。研究结果表明,随着岩石试件高度的降低,岩爆临界破坏强度有升高的趋势。岩石岩爆破坏后破裂面特征随着试件高度的降低而发生明显变化,经历了由劈裂张拉破坏为主向剪切破坏为主破坏模式的转变。同时,试验中表征损伤的声发射能率参数随着试件高度的降低有增大的趋势,即释能速度越来越快。对试验各典型阶段产生的AE特征波形进行提取并采用快速傅里叶变换方法处理,对比频谱图发现,花岗岩岩爆试验过程声发射主频值总体呈"从低频向高频再向低频"转变迁移的趋势,不同高度岩石岩爆试验结果有着相似的谱分布,主频主要集中在90～120 kHz低频区间范围,是该花岗岩岩爆中的最重要特征频率,频谱特征中的高频部分受试件高度的影响而有不同。
Rock size is an important factor influencing its mechanical behavior. Rock burst is a special mechanical response of rock under complex stress conditions. The study of size effect on rock behavior in rock burst is of great importance. A modified true-triaxial apparatus and acoustic emission(AE) monitoring system made by Physical Acoustics Corporation are used to perform laboratory rockburst simulation tests on granite specimens with different heights. The fracture characteristics of rock are observed, and the AE waveforms spectra characteristics are studied. The experimental results indicate that the critical failure stress of rock samples has an increasing trend as the sample height decreases. The fracture surface characteristics of rock after rockburst have undergone a transition from splitting tension failure to shear failure with the decrease of specimen height. Meanwhile, AE energy rate, which can reflect rock damage, increases gradually as the sample height decreases, indicating faster release rate of AE energy. Using fast Fourier transform(FFT) to process extracted waveform files at typical stages, it can be found that rock samples with different heights have a similar variation in the major frequency, which transits from low frequency to high frequency and finally back to low frequency. The most important characteristic frequency, is located in the lower frequency ranges of 90～120 kHz. The high frequency part of the spectrum characteristics varies with the height of the specimen.
Rock size is an important factor influencing its mechanical behavior. Rock burst is a special mechanical response of rock under complex stress conditions. The study of size effect on rock behavior in rock burst is of great importance. A modified true-triaxial apparatus and acoustic emission(AE) monitoring system made by Physical Acoustics Corporation are used to perform laboratory rockburst simulation tests on granite specimens with different heights. The fracture characteristics of rock are observed, and the AE waveforms spectra characteristics are studied. The experimental results indicate that the critical failure stress of rock samples has an increasing trend as the sample height decreases. The fracture surface characteristics of rock after rockburst have undergone a transition from splitting tension failure to shear failure with the decrease of specimen height. Meanwhile, AE energy rate, which can reflect rock damage, increases gradually as the sample height decreases, indicating faster release rate of AE energy. Using fast Fourier transform(FFT) to process extracted waveform files at typical stages, it can be found that rock samples with different heights have a similar variation in the major frequency, which transits from low frequency to high frequency and finally back to low frequency. The most important characteristic frequency, is located in the lower frequency ranges of 90～120 kHz. The high frequency part of the spectrum characteristics varies with the height of the specimen.
引文
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[14]贾雪娜.应变岩爆试验的声发射本征频谱特征[D].北京:中国矿业大学(北京),2013.JIA Xue-na.Experimental study on acoustic emission eigen-frequency spectrum features of strain bursts[D].Beijing:China University of Mining and Technology(Beijing),2013.
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[16]HIRATA A,KAMEOKA Y,HIRANO T.Safety management based on detection of possible rock bursts by AE monitoring during tunnel excavation[J].Rock Mechanics and Rock Engineering,2007,40(6):563-576.
[17]HE M C,NIE W,ZHAO Z Y,et al.Experimental investigation of bedding plane orientation on the rockburst behavior of sandstone[J].Rock Mechanics and Rock Engineering,2012,45(3):311-326.
[18]姚旭龙,张艳博,刘祥鑫,等.岩石破裂声发射关键特征信号优选方法[J].岩土力学,2018,39(1):375-384.YAO Xu-long,ZHANG Yan-bo,LIU Xiang-xin,et al.Optimization method for key characteristic signal of acoustic emission in rock fracture[J].Rock and Soil Mechanics,2018,39(1):375-384.
[19]刘飞跃,杨天鸿,张鹏海,等.基于声发射的岩石破裂应力场动态反演[J].岩土力学,2018,39(4):1517-1524.LIU Fei-yue,YANG Tian-hong,ZHANG Peng-hai,et al.Dynamic inversion of rock fracturing stress field based on acoustic emission[J].Rock and Soil Mechanics,2018,39(4):1517-1524.
[20]LOCKNER D.The role of acoustic emission in the study of rock fracture[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,1993,30(7):883-899.
[21]张永升.波形分析方法在碳酸盐岩储层预测中的应用[J].石油物探,2004,43(2):135-138.ZHANG Yong-sheng.Prediction for carbonate reservoirs by waveform analysis[J].Geophysical Prospecting for Petroleum,2004,43(2):135-138.
[22]李海鹏,隋波,彭军.波形分析影响因素分析[J].内蒙古石油化工,2013,39(20):21-23.LI Hai-peng,SUI Bo,PENG Jun.The analysis of factors influencing the waveform analysis[J].Inner Mongolia Petrochemical Industry,2013,39(20):21-23.
[2]李宏,朱浮声,王泳嘉,等.岩石统计细观损伤与局部弱化失稳的尺寸效应[J].岩石力学与工程学报,1999,18(1):28-32.LI Hong,ZHU Fu-sheng,WANG Yong-jia,et al.Size effect of statistical meso-damage and local softening instability of rock[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(1):28-32.
[3]倪红梅,杨圣奇.单轴压缩下岩石材料尺寸效应的数值模拟[J].煤田地质与勘探,2005,33(5):47-49.NI Hong-mei,YANG Sheng-qi.Numerical simulation on size effect of rock material under uniaxial compression[J].Coal Geology&Exploration,2005,33(5):47-49.
[4]刘宝琛,张家生,杜奇中,等.岩石抗压强度的尺寸效应[J].岩石力学与工程学报,1998,17(6):611-614.LIU Bao-chen,ZHANG Jia-sheng,DU Qi-zhong,et al.Astudy of size effect for compression strength of rock[J].Chinese Journal of Rock Mechanics and Engineering,1998,17(6):611-614.
[5]梁昌玉,李晓,张辉,等.中低应变率范围内花岗岩单轴压缩特性的尺寸效应研究[J].岩石力学与工程学报,2013,32(3):528-536.LIANG Chang-yu,LI Xiao,ZHANG Hui,et al.Research on size effect of uniaxial compression properties of granite under medium and low strain rates[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):528-536.
[6]王学滨,潘一山,宋维源.岩石试件尺寸效应的塑性剪切应变梯度模型[J].岩土工程学报,2001,23(6):711-713.WANG Xue-bin,PAN Yi-shan,SONG Wei-yuan.The model of plastic shear strain gradient on size effect in uniaxial compression of rock specimen[J].Chinese Journal of Geotechnical Engineering,2001,23(6):711-713.
[7]潘一山,魏建明.岩石材料应变软化尺寸效应的试验和理论研究[J].岩石力学与工程学报,2002,21(2):215-218.PAN Yi-shan,WEI Jian-ming.Experimental and theoretical study on size effect on stain softening of rock materials[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(2):215-218.
[8]杨圣奇,徐卫亚.不同围压下岩石材料强度尺寸效应的数值模拟[J].河海大学学报(自然科学版),2004,32(5):578-582.YANG Sheng-qi,XU Wei-ya.Numerical simulation of strength size effect of rock materials under different confining pressures[J].Journal of Hohai University(Natural Sciences),2004,32(5):578-582.
[9]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):1593-1603.MIAO Jin-li,HE Man-chao,LI De-jian,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):1593-1603.
[10]康勇,李晓红,王青海,等.隧道地应力测试及岩爆预测研究[J].岩土力学,2005,26(6):959-963.KANG Yong,LI Xiao-hong,WANG Qing-hai,et al.Research on in-situ stress measurement and rockburst forecast in tunnels[J].Rock and Soil Mechanics,2005,26(6):959-963.
[11]刘宁,张春生,褚卫江,等.深埋大理岩力学特性对岩爆发生条件的影响分析[J].岩土力学,2013,34(9):2638-2642.LIU Ning,ZHANG Chun-sheng,CHU Wei-jiang,et al.Influence of mechanical characteristics of deep-buried marble on rockburst occurrence conditions[J].Rock and Soil Mechanics,2013,34(9):2638-2642.
[12]滕伟福,胡新丽,唐辉明.岩石全应力-应变试验与岩爆理论研究[J].岩土力学,2002,23(增刊1):59-61.TENG Wei-fu,HU Xin-li,TANG Hui-ming.Study on the rock stress-strain test and rock pressure burst theory[J].Rock and Soil Mechanics,2003,23(Supp.1):59-61.
[13]唐礼忠,潘长良.冬瓜山铜矿深井开采岩爆危险区分析与预测[J].中南工业大学学报(自然科学版),2002,33(4):335-338.TANG Li-zhong,PAN Chang-liang.Analysis and prediction of rock burst dangerous areas in Dongguashan copper mine under deep well mining[J].Journal of Center South University Technology,2002,33(4):335-338.
[14]贾雪娜.应变岩爆试验的声发射本征频谱特征[D].北京:中国矿业大学(北京),2013.JIA Xue-na.Experimental study on acoustic emission eigen-frequency spectrum features of strain bursts[D].Beijing:China University of Mining and Technology(Beijing),2013.
[15]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.
[16]HIRATA A,KAMEOKA Y,HIRANO T.Safety management based on detection of possible rock bursts by AE monitoring during tunnel excavation[J].Rock Mechanics and Rock Engineering,2007,40(6):563-576.
[17]HE M C,NIE W,ZHAO Z Y,et al.Experimental investigation of bedding plane orientation on the rockburst behavior of sandstone[J].Rock Mechanics and Rock Engineering,2012,45(3):311-326.
[18]姚旭龙,张艳博,刘祥鑫,等.岩石破裂声发射关键特征信号优选方法[J].岩土力学,2018,39(1):375-384.YAO Xu-long,ZHANG Yan-bo,LIU Xiang-xin,et al.Optimization method for key characteristic signal of acoustic emission in rock fracture[J].Rock and Soil Mechanics,2018,39(1):375-384.
[19]刘飞跃,杨天鸿,张鹏海,等.基于声发射的岩石破裂应力场动态反演[J].岩土力学,2018,39(4):1517-1524.LIU Fei-yue,YANG Tian-hong,ZHANG Peng-hai,et al.Dynamic inversion of rock fracturing stress field based on acoustic emission[J].Rock and Soil Mechanics,2018,39(4):1517-1524.
[20]LOCKNER D.The role of acoustic emission in the study of rock fracture[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,1993,30(7):883-899.
[21]张永升.波形分析方法在碳酸盐岩储层预测中的应用[J].石油物探,2004,43(2):135-138.ZHANG Yong-sheng.Prediction for carbonate reservoirs by waveform analysis[J].Geophysical Prospecting for Petroleum,2004,43(2):135-138.
[22]李海鹏,隋波,彭军.波形分析影响因素分析[J].内蒙古石油化工,2013,39(20):21-23.LI Hai-peng,SUI Bo,PENG Jun.The analysis of factors influencing the waveform analysis[J].Inner Mongolia Petrochemical Industry,2013,39(20):21-23.