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| Macro-crack propagation process and corresponding AE behaviors of fractured sandstone under different loading rates#br# |
| WANG Xiaoran1，2，3，WANG Enyuan1，2，LIU Xiaofei1，2，LI Xuelong4，WANG Hao1，2，LI Dexing1，2 |
(1. Key Laboratory of Gas and Fire Control for Coal Mines，Ministry of Education，China University of Mining and Technology， Xuzhou，Jiangsu 221116，China；2. School of Safety Engineering，China University of Mining and Technology，Xuzhou，
Jiangsu 221116，China；3. Department of Civil，Environmental and Geo-engineering，University of Minnesota-twin
Cities Campus，Minneapolis，MN 55455，USA；4. State Key Laboratory of Coal Mine Disaster Dynamics and Control，
Chongqing University，Chongqing 400044，China) |
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Abstract The geodynamic disaster is the process of development and nucleation of fractured structures in rock mass. With the aid of acoustic emission(AE) monitoring，the failure process can be monitored to realize the accurate early-warning of the disasters. In this paper，the AE response varying with time including the AE counts，multifractal and frequency spectrum of fractured sandstone were measured in the entire loading process under different loading rates. The AE behaviors at the key points of crack propagation and the loading rate effects were studied using 3D locating according to the AE events. The loading rate was found to have significant effects on the propagation of macro-cracks and AE behaviors of fractured sandstone. The peak AE counts，the multifractal spectrum width ，and the amplitude of dominant frequency increase gradually but the dominant frequency and multifractal decrease gradually with the increasing of loading rates. The dynamic and nonlinear characteristics of rock failure process become more obvious，and the failure modes change from shear failure to tensile failure. In the whole loading process，the AE counts，the multifractal spectrum width and the low frequency component proportion increase gradually，while the multifractal parameter decreases gradually with the increasing of axial stress. The AE multifractal and spectral parameters show fluctuation characteristics，and the AE counts show“pulse + calm”feature for multiple times when the sandstone specimen enters into the meta-instable stage. These time-varying trends of AE can be used to early-warn the dynamic disaster. The initiation，propagation，coalescence and nucleation of macro-cracks are the processes of rupture of locked bodies inside rock. An event of fracturing of locked body corresponds to a drop of stress，a large value of AE count，and an extremum value of the multifractal and spectral parameters. The loading rate effects and the AE response precursor behaviors of repeated suddenly increasing then quiet at the meta-instable stage can all be explained reasonably with the established theory of rupture nucleation of multiple locked bodies.
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[1] 何满潮，谢和平，彭苏萍，等. 深部开采岩体力学研究[J]. 岩石力学与工程学报，2005，24(16)：2 803–2 813.(HE Manchao，XIE Heping，PENG Suping，et al. Study on rock mechanics in deep mining engineering[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(16)：2 803–2 813.(in Chinese))
[2] 李浩然，杨春和，李佰林，等. 三轴多级载荷下盐岩声波声发射特征与损伤演化规律研究[J]. 岩石力学与工程学报，2016，35(4)：682–691.(LI Haoran，YANG Chunhe，LI Bailin，et al. Damage evolution and characteristics of ultrasonic velocity and acoustic emission for salt rock under triaxial multilevel loading test[J]. Chinese Journal of Rock Mechanics and Engineering，2016，35(4)：682–691. (in Chinese))
[3] KONG B，WANG E Y，LI Z H，et al. Electromagnetic radiation characteristics and mechanical properties of deformed and fractured sandstone after high temperature treatment[J]. Engineering Geology，2016，209(15)：82–92.
[4] 马 瑾，郭彦双. 失稳前断层加速协同化的实验室证据和地震实例[J]. 地震地质，2014，36(3)：547–561.(MA Jin，GUO Yanshuang. Accelerated synergism prior to fault instability：evidence from laboratory experiments and an earthquake case[J]. Seismology and Geology，2014，36(3)：547–561.(in Chinese))
[5] 王学滨，吕家庆，马 冰，等. 断层间距对拉张雁列构造破坏过程及能量释放影响的模拟[J]. 地球物理学进展，2014，29(1)：406–411.(WANG Xuebing，LV Jiaqing，MA Bing，et al. Effect of fault spacing on the deformation，failure process and released energy for the extensional echelon faults：a numerical simulation[J]. Process in Geophysics，2014，29(1)：406–411.(in Chinese))
[6] 潘一山，王来贵，章梦涛，等. 断层冲击地压发生的理论与试验研究[J]. 岩石力学与工程学报，1998，17(6)：642–649.(PAN Yishan，WANG Laigui，ZHANG Mengtao，et al. The theoretical and testing study of fault rock burst[J]. Chinese Journal of Rock Mechanics and Engineering，1998，17(6)：642–649.(in Chinese))
[7] 姜耀东，潘一山，姜福兴，等. 我国煤炭开采中的冲击地压机理和防治[J]. 煤炭学报，2014，39(2)：205–213.(JIANG Yaodong，PAN Yishan，JIANG Fuxing，et al. State of the art review on mechanism and prevention of coal bumps in China[J]. Journal of China Coal Society，2014，39(2)：205–213.(in Chinese))
[8] PROCHAZKA P P. Application of discrete element methods to fracture mechanic of rock bursts[J]. Engineering Fracture Mechanics，2004，71(4–6)：601–618.
[9] WANG E Y，HE X Q，WEI J P，et al. Electromagnetic emission graded warning model and its applications against coal rock dynamic collapses[J]. International Journal of Rock Mechanics and Mining Science，2011，48：556–564.
[10] 秦四清，李造鼎，林韵梅. 岩石破裂的微观过程与声发射[J]. 东北工学院学报，1991，12(3)：247–253.(QIN Siqing，LI Zaoding，LIN Yunmei. Microprocess of rock fracture and acoustic emission[J]. Journal of Northeast University of Technology，1991，12(3)：247–253.(in Chinese))
[11] WANG X R，LIU X F，WANG E Y，et al. Experimental research of the AE responses and fracture evolution characteristics for sand-paraffin similar material[J]. Construction and Building Materials，2017，(132)：446–456.
[12] 艾 婷，张 茹，刘建锋，等. 三轴压缩煤岩破裂过程中声发射时空演化规律[J]. 煤炭学报，2011，36(12)：2 048–2 057.(AI Ting，ZHANG Ru，LIU Jianfeng，et al. Space-time evolution rules of acoustic emission locations under triaxial compression[J]. Journal of China Coal Society，2011，36(12)：2 048–2 057.(in Chinese))
[13] TSUYOSHI I，JOSEPH F L，GERD M，et al. ISRM suggested method for laboratory acoustic emission monitoring[J]. Rock mechanics and Rock Engineering，2017，50：665–674.
[14] PETER J D G ，PETER A M W，ROGER B F J. Real-time frequency determination of acoustic emission for different fracture mechanisms in carbon/epoxy composites[J]. Composites Science and Technology，1995，55(4)：405–412.
[15] KONG B，WANG E Y，LI Z H，et al. Acoustic emission signals frequency-amplitude characteristics of sandstone after thermal treated under uniaxial compression[J]. Journal of Applied Geophysics，2017，136：190–197.
[16] 蔡江东，陈亚东，张道明. 基于多重分形的岩石声发射信号特征解构分析[J]. 地下空间与工程学报，2007，8(5)：963–968.(CAI Jiangdong，CHEN Yadong，ZHANG Daoming. Study on the feature of acoustic emission of rock under compression experiment based on multi-fractal theory[J]. Chinese Journal of Underground Space and Engineering，2007，8(5)：963–968.(in Chinese))
[17] 胡少斌，王恩元，李忠辉，等. 受载煤体电磁辐射动态非线性特征[J]. 中国矿业大学学报，2014，43(3)：380–387.(HU Shaobin，WANG Enyuan，LI Zhonghui，et al. Nonlinear dynamic characteristics of electromagnetic radiation during loading coal[J]. Journal of China University of Mining and technology，2014，43(3)：380–387.(in Chinese))
[18] 王笑然，王恩元，刘晓斐，等. 含雁行裂纹砂岩静态加载速率效应实验研究[J]. 煤炭学报，2017，42(10)：2 582–2 591.(WANG Xiaoran，WANG Enyuan，LIU Xiaofei，et al. Experimental study on the static loading rate effects of sandstone specimen containing pre-existing echelon cracks[J]. Journal of China Coal Society，2017，42(10)：2 582–2 591.(in Chinese))
[19] 王金安，焦申华，谢广祥. 综放工作面开采速率对围岩应力环境影响的研究[J]. 岩石力学与工程学报，2006，25(6)：1 118–1 124. (WANG Jinan，JIAO Shenhua，XIE Guangxiang. Study on influence of mining rate on stress environment in surrounding rock of mechanized top caving mining face[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(6)：1 118–1 124.(in Chinese))
[20] 李海涛. 加载速率效应影响下煤的冲击特性评价方法及应用[博士学位论文][D]. 北京：中国矿业大学(北京)，2014.(LI Haitao. Evaluation method and application of coal burst performance under the effect of loading rate[Ph. D. Thesis][D]. Beijing：China University of Mining and Technology(Beijing)，2014.(in Chinese))
[21] LIU X F，WANG X R，WANG E Y，et al. Effects of gas pressure on bursting liability of coal under uniaxial conditions[J]. Journal of Natural Gas Science and Engineering，2017，(39)：90–100.
[22] 王笑然，刘晓斐，沈荣喜，等. 自然和饱水煤样受载破坏声发射特征实验研究[J]. 煤矿安全，2016，47(1)：28–32.(WANG Xiaoran，LIU Xiaofei，SHEN Rongxi，et al. Experimental study on AE characteristics of natural and water-saturated coal in process of deformation and fracture[J]. Safety in Coal Mines，2016，47(1)：28–32.(in Chinese))
[23] 陆菜平，窦林名，吴兴荣，等. 煤岩冲击前兆微震频谱演变规律的试验与实证研究[J]. 岩石力学与工程学报，2008，27(3)：519–525. (LU Caiping，DOU Linming，WU Xingrong，et al. Experimental and empirical research on frequency-spectrum evolvement rule of rockburst precursory microseismic signals of coal-rock[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(3)：519–525. (in Chinese))
[24] HU S B，WANG E Y，LI Z H，et al. Time-varying multifractal characteristics and formation mechanism of loaded coal electromagnetic radiation[J]. Rock Mechanics and Rock Engineering，2014，47(5)：1 821–1 838.
[25] 黄润秋，陈国庆，唐 鹏. 基于动态演化特征的锁固段型岩质滑坡前兆信息研究[J]. 岩石力学与工程学报，2017，36(3)：521–533. (HUANG Runqiu，CHEN Guoqing，TANG Peng. Precursor information of locking segment landslides based on transient characteristics[J]. Chinese Journal of Rock Mechanics and Engineering，2017，36(3)：521–533.(in Chinese))
[26] 秦四清，徐锡伟，胡 平，等. 孕震断层的多锁固段脆性破裂机制与地震预测新方法的探索[J]. 地球物理学报，2010，53(4)：1 001–1 014.(QIN Siqing，XU Xiwei，HU Ping，et al. Brittle failure mechanism of multiple locked patches in a seismogenic fault system and exploration on a new way for earthquake prediction[J]. Chinese Journal of Geophysics，2010，53(4)：1 001–1 014.(in Chinese))
[27] ZHURKOV S N，KUKSENKO V S，PETROV V A. Principles of the kinetic approach of fracture prediction[J]. Theoretical and Applied Fracture Mechanics，1984，1(3)：271–274.
[28] 李学龙. 裂隙煤岩动态破裂行为与冲击失稳机制研究[博士学位论文][D]. 徐州：中国矿业大学，2017.(LI Xuelong. Research on dynamic fracture process and rockburst mechanism of cracked coal rock[Ph. D Thesis][D]. Xuzhou：China University of Mining and Technology，2017.(in Chinese))
[29] 冯德益，潘琴龙，郑斯华，等. 长周期形变波及其所反应的短期和临震地震前兆[J]. 地震学报，1984，6(1)：41–57.(FENG Deyi，PAN Qinlong，ZHENG Sihua，et al. Long-period deformational waves and short-term and imminent earthquake precursors[J]. Acta Seismologica Sinica，1984，6(1)：41–57.(in Chinese))
[30] 万志军，李学华，刘长友. 加载速率对岩石声发射活动的影响[J]. 辽宁工程技术大学学报：自然科学版，2001，20(4)：469–471.(WAN Zhijun，LI Xuehua，LIU Changyou. Influence of loading velocity on the rock?s acoustic emission activity[J]. Journal of Liaoning Technical University：Natural Science，2001，20(4)：469–471.(in Chinese)) |
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2018, Vol. 37 
