增量循环加卸载下岩石峰值强度前声发射特性试验研究
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摘要
为了研究岩石峰值强度前声发射前兆特性、加卸载过程的声发射特性,以指导声发射技术在岩体工程监测和灾害预警中的应用,采用花岗闪长岩、角岩、矽卡岩、铜矿、钨钼矿和铅锌矿共6种岩石分别开展单轴压缩、增量循环加卸载和增量稳压循环加卸载3种不同加载方式的试验,主要对岩样峰值强度前声发射相对平静期、卸载过程的声发射特性、对2种不同循环加卸载方式下的Felicity比以及加卸载响应比的变化情况进行研究。试验结果表明,3种加载方式下部分岩样始终存在"相对平静期"现象,多种岩样的AE事件峰值频率在破坏前总是低频成分显著增加,且越接近破坏,大振幅AE事件就越多。在2种不同循环加卸载方式下,当应力水平达到峰值强度的50%～60%时,Kaiser效应逐渐消失,Felicity效应出现。Felicity比和加卸载响应比在低应力水平阶段均大于1,进入中等应力水平阶段后在1附近波动,但相对比较稳定;进入较高应力水平以后,岩石内部裂纹不稳定扩展,Felicity比逐渐减小,到0.64～0.89时,试样破坏。试验表明,相对平静期、Felicity比和加卸载响应比等可作为预测或判断岩石失稳破坏的参考依据。
In order to study the precursory characteristics of acoustic emission before the peak strength and the acoustic emission characteristics of the loading-unloading process for guiding the application of AE technology in rock mass engineering monitoring and disaster warning, six kinds of rocks including granodiorite,hornfels,skarn,copper ore,wolfram-molybdenum ore and lead-zinc ore were tested respectively under uniaxial compression,incremental cyclic loading-unloading and incremental isobaric cyclic loading-unloading,and the relative tranquil period of acoustic emission before the peak strength,the AE characteristics of unloading process,the Felicity ratio under two different cyclic loading-unloading modes and changes of the load-unload response ratio were studied. The results show that some rocks always present the"relatively tranquil period"phenomenon under three different loading modes. The low frequency components of the AE events of a variety of rock samples increase significantly before failure,and the closer to the failure, the more the large amplitudes AE events. Under two different cyclic loading and unloading ways,Felicity effect occurs with Kaiser effect disappearing when the stress level reaches 50% to 60% of the peak intensity. Both Felicity ratio and load-unload response ratio are greater than 1 in the low stress level and fluctuate around 1 in the middle stress level. In the high stress level stage,the internal cracks of the rocks expand unstably with the Felicity ratio reducing and the load-unload response ratio increasing,and the samples destroy when the Felicity ratio reduces to 0.64–0.89. The Felicity ratio and the load-unload response ratio of the relatively tranquil period may be used as the parameters of rock failure prediction.
In order to study the precursory characteristics of acoustic emission before the peak strength and the acoustic emission characteristics of the loading-unloading process for guiding the application of AE technology in rock mass engineering monitoring and disaster warning, six kinds of rocks including granodiorite,hornfels,skarn,copper ore,wolfram-molybdenum ore and lead-zinc ore were tested respectively under uniaxial compression,incremental cyclic loading-unloading and incremental isobaric cyclic loading-unloading,and the relative tranquil period of acoustic emission before the peak strength,the AE characteristics of unloading process,the Felicity ratio under two different cyclic loading-unloading modes and changes of the load-unload response ratio were studied. The results show that some rocks always present the"relatively tranquil period"phenomenon under three different loading modes. The low frequency components of the AE events of a variety of rock samples increase significantly before failure,and the closer to the failure, the more the large amplitudes AE events. Under two different cyclic loading and unloading ways,Felicity effect occurs with Kaiser effect disappearing when the stress level reaches 50% to 60% of the peak intensity. Both Felicity ratio and load-unload response ratio are greater than 1 in the low stress level and fluctuate around 1 in the middle stress level. In the high stress level stage,the internal cracks of the rocks expand unstably with the Felicity ratio reducing and the load-unload response ratio increasing,and the samples destroy when the Felicity ratio reduces to 0.64–0.89. The Felicity ratio and the load-unload response ratio of the relatively tranquil period may be used as the parameters of rock failure prediction.
引文
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[16]李楠,王恩元.岩石循环加载和分级加载损伤破坏声发射实验研究[J].煤炭学报,2010,35(7):1 099-1 103.(LI Nan,WANG Enyuan.Experiment on acoustic emission of rock damage and fracture under cyclic loading and multi-stage loading[J].Journal of China Coal Society,2010,35(7):1 099-1 103.(in Chinese))
[17]周家文,杨兴国,符文熹,等.脆性岩石单轴循环加卸载试验及断裂损伤力学特性研究[J].岩石力学与工程学报,2010,29(6):1 172-1 183.(ZHOU Jiawen,YANG Xingguo,FU Wenxi,et al.Research on transient characteristics of excavation unloading[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(6):1 172-1 183.(in Chinese))
[18]李庶林,林朝阳,毛建喜,等.单轴多级循环加载岩石声发射分形特性试验研究[J].工程力学,2015,32(9):92-99.(LI Shulin,LINChaoyang,MAO Jianxi,et al.Experimental study on fractal dimension characteristics of acoustic emission of rock under multilevel uniaxial cyclic loading[J].Engineering Mechanics,2015,32(9):92-99.(in Chinese))
[19]徐速超,冯夏庭,陈炳瑞.矽卡岩单轴循环加卸载试验及声发射特性研究[J].岩土力学,2009,30(10):2 929-2 934.(XU Suchao,FENG Xiating,CHEN Bingrui.Experimental study of skarn under uniaxial cyclic loading and unloading test and acoustic emission characteristics[J].Rock and Soil Mechanics,2009,30(10):2 929-2 934.(in Chinese))
[20]纪洪广,侯昭飞,张磊,等.载荷岩石材料在加载-卸荷扰动作用下声发射特性[J].北京科技大学学报,2011,33(1):1-5.(JIHongguang,HOU Zhaofei,ZHANG Lei,et al.Acoustic emission character of loaded rock under load-unload disturbance[J].Journal of University of Science and Technology Beijing,2011,33(1):1-5.(in Chinese))
[21]李世愚.岩石断裂力学导论[M].合肥:中国科技大学出版社,2010:288-297.(LI Shiyu.Introduction of rock fracture mechanics[M].Hefei:Press of University of Science and Technology of China,2010:288-297.(in Chinese))
[22]纪洪广.混凝土材料声发射性能研究与应用[M].北京:煤炭工业出版社,2004:134-158.(JI Hongguang.Research and application of acoustic emission performance in concrete materials[M].Beijing:Coal Industry Press,2004:134-158.(in Chinese))
[23]尹祥础,陈学忠,宋治平,等.加卸载响应比--一种新的地震预报方法[J].地球物理学报,1994,37(6):767-775.(YIN Xiangchu,CHEN Xuezhong,SONG Zhiping,et al.The load-unload response ratio theory:A new approach to earth quake prediction[J].Chinese Journal of Geophysics,1994,37(6):767-775.(in Chinese))
[24]余怀忠,尹祥础,夏蒙棼,等.加卸载响应比(LURR)理论的实验研究[J].中国地震,2003,19(1):58-66.(YU Huaizhong,YINXiangchu,XIA Mengfen,et al.Experimental research on the theory of Load/Unload Response Ration(LURR)[J].Earthquake Research in China,2003,19(1):58-66.(in Chinese))
[25]SURESH S.Crack initiation in cyclic compression and its application[J].Engineering Fracture Mechanics,1985,21(3):453-463.
[26]马胜利,蒋海昆,扈小燕,等.基于声发射实验结果讨论大震前地震活动平静现象的机制[J].地震地质,2004,26(3):426-435.(MAShengli,JIANG Haikun,HU Xiaoyan,et al.A discussion on mechanism for seismic quiescence before large earthquakes based on experimental results of acoustic emission[J].Seismology and Geology,2004,26(3):426-435.(in Chinese))
[27]FORTIN J,STANCHITS S,DRESEN G,et al.Acoustic emission monitoring during inelastic deformation of porous sandstone:comparison of three modes of deformation[J].Rock Physics and Natural Hazards,2009,166:823-841.
[2]勝山邦久.声发射(AE)技术的应用[M].冯夏庭译.北京:冶金工业出版社,1996:3-7.(KATSUYAMA K.Application of AE techniques[M].Translated by FENG Xiating.Beijing:China Metallurgical Industry Press,1996:3-7.(in Chinese))
[3]LOCKNER D A.The role of acoustic emission in the study of rock failure[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstract,1993,30(7):883-899.
[4]陈颙.声发射技术在岩石力学中的应用[J].地球物理学报,1977,20(4):312-322.(CHEN Yong.Application of AE techniques to rock mechanics[J].Chinese Journal of Geophysics,1977,20(4):312-322.(in Chinese))
[5]RUDAJEV V,VILHELM J,LOKAJICEK T.Laboratory studies of acoustic emission prior to uniaxial compressive rock failure[J].International Journal of Rock Mechanics and Mining Sciences,2000,37(4):699-704.
[6]吴刚,赵震洋.不同应力状态下岩石类材料破坏的声发射特性[J].岩土工程学报,1998,20(2):82-85.(WU Gang,ZHAO Zhenyang.Acoustic emission character of rock materials failure during various stress states[J].Chinese Journal of Geotechnical Engineering,1998,20(2):82-85.(in Chinese))
[7]刘新平,刘英,陈顒.单轴压缩条件下岩石样品声发射信号的频谱分析[J].声学学报,1986,11(2):80-87.(LIU Xinping,LIUYing,CHEN Yong.Spectral analysis of acoustic emissions of rock specimen during uniaxial compression[J].Acta Acustica,1986,11(2):80-87.(in Chinese))
[8]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):2 499-2 503.(LIShulin,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):2 499-2 503.(in Chinese))
[9]孙强,薛雷.砂岩脆性破坏过程中声发射信息试验研究[J].固体力学学报,2012,33(5):541-547.(SUN Qiang,XUE Lei.Research on AE variation of sandstone brittle failure with along loading by uniaxial compression[J].Chinese Journal of Solid Mechanics,2012,33(5):541-547.(in Chinese))
[10]黄玉仁,林朝阳,毛建喜,等.武夷山隧道围岩破坏过程中的声发射特性研究[J].厦门大学学报:自然科学版,2015,54(2):292-296(HUANG Yuren,LIN Chaoyang,MAO Jianxi,et al.Studies on acoustic emission characteristics of tunnel surrounding rock of Wuyi Mountain[J].Journal of Xiamen University:Natural Science,2015,54(2):292-296.(in Chinese))
[11]MOGI K.Experimental rock mechanics[M].London:Taylor and Francis Group,2007:277-302.
[12]RAO M V M S,RAMANA Y V.A study of progressive failure of rock under cyclic loading by ultrasonic and AE monitoring techniques[J].Rock Mechanics and Rock Engineering,1992,25(4):237-251.
[13]SONDERGELD C H,ESTEY L H.Acoustic emission study of microfracturing during the cyclic loading of Westerly granite[J].Journal of Geophysical Research,1981,86(B4):2 915-2 924.
[14]李庶林,唐海燕.不同加载条件下岩石材料破裂过程的声发射特性研究[J].岩土工程学报,2010,32(1):147-152.(LI Shulin,TANGHaiyan.Acoustic emission characteristics in failure process of rock under different uniaxial compressive loads[J].Chinese Journal of Geotechnical Engineering,2010,32(1):147-152.(in Chinese))
[15]夏冬,杨天鸿,王培涛,等.干燥及饱和岩石循环加卸载过程中声发射特征试验研究[J].煤炭学报,2014,39(7):1 243-1 247.(XIADong,YANG Tianhong,WANG Peitao,et al.Experimental study of acoustic emission characteristics of dry saturated rocks during cyclic loading and unloading process[J].Journal of China Coal Society,2014,39(7):1 243-1 247.(in Chinese))
[16]李楠,王恩元.岩石循环加载和分级加载损伤破坏声发射实验研究[J].煤炭学报,2010,35(7):1 099-1 103.(LI Nan,WANG Enyuan.Experiment on acoustic emission of rock damage and fracture under cyclic loading and multi-stage loading[J].Journal of China Coal Society,2010,35(7):1 099-1 103.(in Chinese))
[17]周家文,杨兴国,符文熹,等.脆性岩石单轴循环加卸载试验及断裂损伤力学特性研究[J].岩石力学与工程学报,2010,29(6):1 172-1 183.(ZHOU Jiawen,YANG Xingguo,FU Wenxi,et al.Research on transient characteristics of excavation unloading[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(6):1 172-1 183.(in Chinese))
[18]李庶林,林朝阳,毛建喜,等.单轴多级循环加载岩石声发射分形特性试验研究[J].工程力学,2015,32(9):92-99.(LI Shulin,LINChaoyang,MAO Jianxi,et al.Experimental study on fractal dimension characteristics of acoustic emission of rock under multilevel uniaxial cyclic loading[J].Engineering Mechanics,2015,32(9):92-99.(in Chinese))
[19]徐速超,冯夏庭,陈炳瑞.矽卡岩单轴循环加卸载试验及声发射特性研究[J].岩土力学,2009,30(10):2 929-2 934.(XU Suchao,FENG Xiating,CHEN Bingrui.Experimental study of skarn under uniaxial cyclic loading and unloading test and acoustic emission characteristics[J].Rock and Soil Mechanics,2009,30(10):2 929-2 934.(in Chinese))
[20]纪洪广,侯昭飞,张磊,等.载荷岩石材料在加载-卸荷扰动作用下声发射特性[J].北京科技大学学报,2011,33(1):1-5.(JIHongguang,HOU Zhaofei,ZHANG Lei,et al.Acoustic emission character of loaded rock under load-unload disturbance[J].Journal of University of Science and Technology Beijing,2011,33(1):1-5.(in Chinese))
[21]李世愚.岩石断裂力学导论[M].合肥:中国科技大学出版社,2010:288-297.(LI Shiyu.Introduction of rock fracture mechanics[M].Hefei:Press of University of Science and Technology of China,2010:288-297.(in Chinese))
[22]纪洪广.混凝土材料声发射性能研究与应用[M].北京:煤炭工业出版社,2004:134-158.(JI Hongguang.Research and application of acoustic emission performance in concrete materials[M].Beijing:Coal Industry Press,2004:134-158.(in Chinese))
[23]尹祥础,陈学忠,宋治平,等.加卸载响应比--一种新的地震预报方法[J].地球物理学报,1994,37(6):767-775.(YIN Xiangchu,CHEN Xuezhong,SONG Zhiping,et al.The load-unload response ratio theory:A new approach to earth quake prediction[J].Chinese Journal of Geophysics,1994,37(6):767-775.(in Chinese))
[24]余怀忠,尹祥础,夏蒙棼,等.加卸载响应比(LURR)理论的实验研究[J].中国地震,2003,19(1):58-66.(YU Huaizhong,YINXiangchu,XIA Mengfen,et al.Experimental research on the theory of Load/Unload Response Ration(LURR)[J].Earthquake Research in China,2003,19(1):58-66.(in Chinese))
[25]SURESH S.Crack initiation in cyclic compression and its application[J].Engineering Fracture Mechanics,1985,21(3):453-463.
[26]马胜利,蒋海昆,扈小燕,等.基于声发射实验结果讨论大震前地震活动平静现象的机制[J].地震地质,2004,26(3):426-435.(MAShengli,JIANG Haikun,HU Xiaoyan,et al.A discussion on mechanism for seismic quiescence before large earthquakes based on experimental results of acoustic emission[J].Seismology and Geology,2004,26(3):426-435.(in Chinese))
[27]FORTIN J,STANCHITS S,DRESEN G,et al.Acoustic emission monitoring during inelastic deformation of porous sandstone:comparison of three modes of deformation[J].Rock Physics and Natural Hazards,2009,166:823-841.