不同应力路径下英安岩声发射b值特征及破坏前兆
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摘要
对英安岩岩样开展单轴、常规三轴加荷和三轴卸荷试验,并对试验过程进行声发射监测,研究在3种应力路径下英安岩变形破坏过程的声发射b值特征差异,探索声发射b值在岩石破坏前兆方面的规律。研究结果表明:英安岩岩样的声发射b值特征与加载的应力路径关系密切,加荷路径即单轴路径和常规三轴路径下b值变化规律相似,加荷与卸荷路径下b值变化规律差异较大。单轴和常规三轴加荷试验中,围压对声发射b值特征有较大的影响。围压越大,岩样在破坏前,b值的整体水平越高。岩样在破坏时,声发射b值下降幅度越大、降低速率越快,且b值达到整个过程中的最小值。三轴卸荷试验中,围压对声发射b值特征影响不明显。与常规三轴试验相比,三轴卸荷试验在卸荷至一定水平后,其b值整体水平更低,最终破坏时b值的最小值更小。提出当岩样峰值强度后存在明显的应力跌落,此时声发射b值的快速下降可以作为破坏前兆。b值的临界值要通过大量室内岩石声发射试验的统计结果来确定。将声发射b值快速下降、临界值突破0. 6作为试验英安岩岩样的破坏前兆。
This paper studies the variation of acoustic emission( AE) characteristics during dacite failure and the rules of AE b value in rock failure precursor. We carry out tests of dacite samples under uniaxial loading,triaxial loading and triaxial unloading conditions. The AE is detected at the same time. The results show that: the change of AE b value is closely related to the stress path. There are significant differences between loading and unloading paths,but the uniaxial loading and the triaxial loading are similar. In uniaxial and triaxial loading tests,the confining pressure has great influence on the change of AE b value. Before rock failure,for the overall AE b value,the higher the confining pressure,the bigger the value. When rock is damaged,the higher the confining pressure,the greater the decline of b value,dropping more rapidly. The b value also reaches its minimum in the whole process. In triaxial unloading test,the effects of confining pressure on the b value is not obvious. Compared with the triaxial loading test,when triaxial unloading tests reach a certain unloading level,the overall b value is lower,and the minimum value of b value is smaller at last. We propose that when rocks reach peak strength and there is a significant stress drop subsequently. The rapid dropping of b value can be used as a precursor to damage. The threshold of b value is determined by a large number of indoor rock AE test results. Rapid drop of the AE b value and b value breaking through 0. 6 can be used as the precursors of rock failure.
This paper studies the variation of acoustic emission( AE) characteristics during dacite failure and the rules of AE b value in rock failure precursor. We carry out tests of dacite samples under uniaxial loading,triaxial loading and triaxial unloading conditions. The AE is detected at the same time. The results show that: the change of AE b value is closely related to the stress path. There are significant differences between loading and unloading paths,but the uniaxial loading and the triaxial loading are similar. In uniaxial and triaxial loading tests,the confining pressure has great influence on the change of AE b value. Before rock failure,for the overall AE b value,the higher the confining pressure,the bigger the value. When rock is damaged,the higher the confining pressure,the greater the decline of b value,dropping more rapidly. The b value also reaches its minimum in the whole process. In triaxial unloading test,the effects of confining pressure on the b value is not obvious. Compared with the triaxial loading test,when triaxial unloading tests reach a certain unloading level,the overall b value is lower,and the minimum value of b value is smaller at last. We propose that when rocks reach peak strength and there is a significant stress drop subsequently. The rapid dropping of b value can be used as a precursor to damage. The threshold of b value is determined by a large number of indoor rock AE test results. Rapid drop of the AE b value and b value breaking through 0. 6 can be used as the precursors of rock failure.
引文
Amitrano D.2003.Brittle-ductile transition and associated seismicity:Experimental and numerical studies and relationship with the b value[J].Journal of Geophysical Research Solid Earth,108(B1):233-236.
Chen G Q,Wang J C,Wang W,et al.2017.Failure characteristics of rock mass with intermittent joints of different connecting rates under direct shear test[J].Journal of Engineering Geology,25(2):322-329.
Cox S J D,Meredith P G.1993.Microcrack formation and material softening in rock measured by monitoring acoustic emissions[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,30(1):11-24.
Fu B,Zhou Z H,Wang H Q,et al.2016.Precursor information study on acoustic emission characteristics of marble under uniaxial cyclic loading-unloading[J].Journal of China Coal Society,41(8):1946-1953.
Gutenberg B,Richter C F.1944.Frequency of earthquakes in California[J].Bulletin of The Seismological Society of America,34(4):185-188.
Han W G,Xiao J,Cui Z D,et al.2017.Acoustic emission characteristics of tight sandstone during failure processes with different confining pressures[J].Journal of Engineering Geology,25(5):1270-1278.
Khazaei C,Hazzard J,Chalaturnyk R.2015.Damage quantification of intact rocks using acoustic emission energies recorded during uniaxial compression test and discrete element modeling[J].Computers and Geotechnics,67:94-102.
Lei X L,Satoh T S.2007.Indicators of critical point behavior prior to rock failure inferred from pre-failure damage[J].Tectonophysics,431(1):97-111.
Li T Y,Liu J F,Chen L,et al.2013.Acoustic emission characteristics of granite under tensile loading[J].Chinese Journal of Rock Mechanics and Engineering,32(S2):3215-3221.
Li Y H,Liu J P,Zhao X D,et al.2009.Study of b-value and fractal dimension of acoustic emission during rock failure process[J].Rock and Soil Mechanics,30(9):2559-2563.
Liang T C,Ge H K,Guo Z W,et al.2012.Evaluation of rock damage state with acoustic emission and velocity variation[J].Earthquake Research in China,28(2):154-166.
Lin G Y,Zhao Q H,Wang C H,et al.2018.Studies on acoustic emission characteristics of cyclic loading-unloading granite failure[J].Journal of Engineering Geology,26(2):475-483.
Liu Q Y,Zhang R,Gao M Z,et al.2016.Acoustic emission characteristics and comprehensive failure precursors of coal under unloading conditions[J].Journal of Sichuan University(Engineering Science Edition),48(S2):67-74.
Qin S Q,Li Z D,Zhang Z Y,et al.1993.An introduction to acoustic emission techniques in rocks[M].Chengdu:Southwest Jiaotong University Press.
Sagar R V,Prasad B K R,Kumar S S.2012.An experimental study on cracking evolution in concrete and cement mortar by the b-value analysis of acoustic emission technique[J].Cement&Concrete Research,42(8):1094-1104.
Townend E,Thompson B D,Benson P M,et al.2008.Imaging compaction band propagation in Diemelstadt sandstone using acoustic emission locations[J].Geophysical Research Letters,35(15):189-193.
Wu X Z,Liu X X,Liang Z Z,et al.2012.Experimental study of fractal dimension of AE serials of different rocks under uniaxial compression[J].Rock and Soil Mechanics,33(12):3561-3569.
Zeng Z W,Ma J,Liu L Q,et al.1995.AE b-value dynamic features of during rock mass fracturing and their significances[J].Seismology and Geology,17(1):7-11.
Zhang L M,Ma S Q,Ren M Y,et al.2015.Acoustic emission frequency and b value characteristics in rock failure process under various confining pressures[J].Chinese Journal of Rock Mechanics and Engineering,34(10):2057-2063.
Zhang L M,Wang Z Q,Shi L,et al.2012.Acoustic emission characteristics of marble during failure process under different stress paths[J].Chinese Journal of Rock Mechanics and Engineering,31(6):1230-1236.
Zhang Y B,Yu G Y,Tian B Z,et al.2017.Experimental study of acoustic emission signal dominant-frequency characteristics of rockburst in a granite tunnel[J].Rock and Soil Mechanics,38(5):1258-1266.
Zhang Z P,Zhang R,Zhang Z T,et al.2015.Experimental research on effects of bedding plane on coal acoustic emission under uniaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,34(4):770-778.
陈国庆,王剑超,王伟,等.2017.不同连通率断续节理岩体直剪破坏特征[J].工程地质学报,25(2):322-329.
付斌,周宗红,王海泉,等.2016.大理岩单轴循环加卸载破坏声发射先兆信息研究[J].煤炭学报,41(8):1946-1953.
韩伟歌,肖吉,崔振东,等.2017.不同围压下致密砂岩破裂过程声发射特征研究[J].工程地质学报,25(5):1270-1278.
李天一,刘建锋,陈亮,等.2013.拉伸应力状态下花岗岩声发射特征研究[J].岩石力学与工程学报,32(增刊2):3215-3221.
李元辉,刘建坡,赵兴东,等.2009.岩石破裂过程中的声发射b值及分形特征研究[J].岩土力学,30(9):2559-2563.
梁天成,葛洪魁,郭志伟,等.2012.利用声发射和波速变化判定岩石损伤状态[J].中国地震,28(2):154-166.
林冠宇,赵其华,王晨辉,等.2018.循环加卸载条件下花岗岩破坏过程声发射特征研究[J].工程地质学报,26(2):475-483.
刘倩颖,张茹,高明忠,等.2016.煤卸荷过程中声发射特征及综合破坏前兆分析[J].四川大学学报(工程科学版),48(增刊2):67-74.
秦四清,李造鼎,张倬元,等.1993.岩石声发射技术概论[M].成都:西南交通大学出版社.
吴贤振,刘祥鑫,梁正召,等.2012.不同岩石破裂全过程的声发射序列分形特征试验研究[J].岩土力学,33(12):3561-3569.
曾正文,马谨,刘力强,等.1995.岩石破裂扩展过程中的声发射b值动态特征及意义[J].地震地质,17(1):7-11.
张朝鹏,张茹,张泽天,等.2015.单轴受压煤岩声发射特征的层理效应试验研究[J].岩石力学与工程学报,34(4):770-778.
张黎明,马绍琼,任明远,等.2015.不同围压下岩石破坏过程的声发射频率及b值特征[J].岩石力学与工程学报,34(10):2057-2063.
张黎明,王在泉,石磊,等.2012.不同应力路径下大理岩破坏过程的声发射特性[J].岩石力学与工程学报,31(6):1230-1236.
张艳博,于光远,田宝柱,等.2017.花岗岩巷道岩爆声发射信号主频特性试验研究[J].岩土力学,38(5):1258-1266.
Chen G Q,Wang J C,Wang W,et al.2017.Failure characteristics of rock mass with intermittent joints of different connecting rates under direct shear test[J].Journal of Engineering Geology,25(2):322-329.
Cox S J D,Meredith P G.1993.Microcrack formation and material softening in rock measured by monitoring acoustic emissions[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,30(1):11-24.
Fu B,Zhou Z H,Wang H Q,et al.2016.Precursor information study on acoustic emission characteristics of marble under uniaxial cyclic loading-unloading[J].Journal of China Coal Society,41(8):1946-1953.
Gutenberg B,Richter C F.1944.Frequency of earthquakes in California[J].Bulletin of The Seismological Society of America,34(4):185-188.
Han W G,Xiao J,Cui Z D,et al.2017.Acoustic emission characteristics of tight sandstone during failure processes with different confining pressures[J].Journal of Engineering Geology,25(5):1270-1278.
Khazaei C,Hazzard J,Chalaturnyk R.2015.Damage quantification of intact rocks using acoustic emission energies recorded during uniaxial compression test and discrete element modeling[J].Computers and Geotechnics,67:94-102.
Lei X L,Satoh T S.2007.Indicators of critical point behavior prior to rock failure inferred from pre-failure damage[J].Tectonophysics,431(1):97-111.
Li T Y,Liu J F,Chen L,et al.2013.Acoustic emission characteristics of granite under tensile loading[J].Chinese Journal of Rock Mechanics and Engineering,32(S2):3215-3221.
Li Y H,Liu J P,Zhao X D,et al.2009.Study of b-value and fractal dimension of acoustic emission during rock failure process[J].Rock and Soil Mechanics,30(9):2559-2563.
Liang T C,Ge H K,Guo Z W,et al.2012.Evaluation of rock damage state with acoustic emission and velocity variation[J].Earthquake Research in China,28(2):154-166.
Lin G Y,Zhao Q H,Wang C H,et al.2018.Studies on acoustic emission characteristics of cyclic loading-unloading granite failure[J].Journal of Engineering Geology,26(2):475-483.
Liu Q Y,Zhang R,Gao M Z,et al.2016.Acoustic emission characteristics and comprehensive failure precursors of coal under unloading conditions[J].Journal of Sichuan University(Engineering Science Edition),48(S2):67-74.
Qin S Q,Li Z D,Zhang Z Y,et al.1993.An introduction to acoustic emission techniques in rocks[M].Chengdu:Southwest Jiaotong University Press.
Sagar R V,Prasad B K R,Kumar S S.2012.An experimental study on cracking evolution in concrete and cement mortar by the b-value analysis of acoustic emission technique[J].Cement&Concrete Research,42(8):1094-1104.
Townend E,Thompson B D,Benson P M,et al.2008.Imaging compaction band propagation in Diemelstadt sandstone using acoustic emission locations[J].Geophysical Research Letters,35(15):189-193.
Wu X Z,Liu X X,Liang Z Z,et al.2012.Experimental study of fractal dimension of AE serials of different rocks under uniaxial compression[J].Rock and Soil Mechanics,33(12):3561-3569.
Zeng Z W,Ma J,Liu L Q,et al.1995.AE b-value dynamic features of during rock mass fracturing and their significances[J].Seismology and Geology,17(1):7-11.
Zhang L M,Ma S Q,Ren M Y,et al.2015.Acoustic emission frequency and b value characteristics in rock failure process under various confining pressures[J].Chinese Journal of Rock Mechanics and Engineering,34(10):2057-2063.
Zhang L M,Wang Z Q,Shi L,et al.2012.Acoustic emission characteristics of marble during failure process under different stress paths[J].Chinese Journal of Rock Mechanics and Engineering,31(6):1230-1236.
Zhang Y B,Yu G Y,Tian B Z,et al.2017.Experimental study of acoustic emission signal dominant-frequency characteristics of rockburst in a granite tunnel[J].Rock and Soil Mechanics,38(5):1258-1266.
Zhang Z P,Zhang R,Zhang Z T,et al.2015.Experimental research on effects of bedding plane on coal acoustic emission under uniaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,34(4):770-778.
陈国庆,王剑超,王伟,等.2017.不同连通率断续节理岩体直剪破坏特征[J].工程地质学报,25(2):322-329.
付斌,周宗红,王海泉,等.2016.大理岩单轴循环加卸载破坏声发射先兆信息研究[J].煤炭学报,41(8):1946-1953.
韩伟歌,肖吉,崔振东,等.2017.不同围压下致密砂岩破裂过程声发射特征研究[J].工程地质学报,25(5):1270-1278.
李天一,刘建锋,陈亮,等.2013.拉伸应力状态下花岗岩声发射特征研究[J].岩石力学与工程学报,32(增刊2):3215-3221.
李元辉,刘建坡,赵兴东,等.2009.岩石破裂过程中的声发射b值及分形特征研究[J].岩土力学,30(9):2559-2563.
梁天成,葛洪魁,郭志伟,等.2012.利用声发射和波速变化判定岩石损伤状态[J].中国地震,28(2):154-166.
林冠宇,赵其华,王晨辉,等.2018.循环加卸载条件下花岗岩破坏过程声发射特征研究[J].工程地质学报,26(2):475-483.
刘倩颖,张茹,高明忠,等.2016.煤卸荷过程中声发射特征及综合破坏前兆分析[J].四川大学学报(工程科学版),48(增刊2):67-74.
秦四清,李造鼎,张倬元,等.1993.岩石声发射技术概论[M].成都:西南交通大学出版社.
吴贤振,刘祥鑫,梁正召,等.2012.不同岩石破裂全过程的声发射序列分形特征试验研究[J].岩土力学,33(12):3561-3569.
曾正文,马谨,刘力强,等.1995.岩石破裂扩展过程中的声发射b值动态特征及意义[J].地震地质,17(1):7-11.
张朝鹏,张茹,张泽天,等.2015.单轴受压煤岩声发射特征的层理效应试验研究[J].岩石力学与工程学报,34(4):770-778.
张黎明,马绍琼,任明远,等.2015.不同围压下岩石破坏过程的声发射频率及b值特征[J].岩石力学与工程学报,34(10):2057-2063.
张黎明,王在泉,石磊,等.2012.不同应力路径下大理岩破坏过程的声发射特性[J].岩石力学与工程学报,31(6):1230-1236.
张艳博,于光远,田宝柱,等.2017.花岗岩巷道岩爆声发射信号主频特性试验研究[J].岩土力学,38(5):1258-1266.