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真三轴加载条件下岩爆过程的声发射演化特征 被引量:17
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作者 苏国韶 燕思周 +2 位作者 闫召富 翟少彬 燕柳斌 《岩土力学》 EI CAS CSCD 北大核心 2019年第5期1673-1682,共10页
利用真三轴岩爆试验系统,对花岗岩开展真三轴加载条件下岩爆过程的声发射试验,初步揭示了岩爆过程中的声发射时空演化特征:岩爆孕育前期,振铃撞击比较小,主频以低频为主,优势频段(基于小波分析能量占比最大频段)为小于125 kHz的低频段,... 利用真三轴岩爆试验系统,对花岗岩开展真三轴加载条件下岩爆过程的声发射试验,初步揭示了岩爆过程中的声发射时空演化特征:岩爆孕育前期,振铃撞击比较小,主频以低频为主,优势频段(基于小波分析能量占比最大频段)为小于125 kHz的低频段,声发射事件点由分散态趋于聚集态,新增事件由临空面向岩样内部方向转移;岩爆发生前夕,振铃撞击比大幅突增,低频、中频、高频信号大量涌现,主频带由离散形态转变为连续形态,250~500 kHz优势频段信号占比明显增加,声发射事件成核区在距临空面较远处成形,临空面附近区域事件点增多;岩爆发生阶段,声发射呈低频高幅特征,优势频段重新转入62.5~125.0 kHz,岩样临空面附近声发射活跃,岩样内部出现明显的声发射事件成核区,表明临空面附近出现了岩板劈裂现象,距临空面较远处出现了宏观剪切破坏现象。 展开更多
关键词 岩石力学 岩爆 真三轴 声发射
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Acoustic emission precursors of static and dynamic instability for coarse-grained hard rock 被引量:13
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作者 SU Guo-shao GAN Wei +1 位作者 zhai shao-bin ZHAO Guo-fu 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第10期2883-2898,共16页
To investigate the acoustic emission(AE)precursors of coarse-grained hard rock instability,an experimental study on the rockburst and slabbing process of granite was carried out using a true triaxial test system.The e... To investigate the acoustic emission(AE)precursors of coarse-grained hard rock instability,an experimental study on the rockburst and slabbing process of granite was carried out using a true triaxial test system.The evolution of the AE signals was monitored and analyzed in terms of the AE hit rate,fractal dimension of the AE hit number,AE count rate,b-value,dominant frequency and microcrack type.The test results show that after rock slabbing occurs,the AE precursors that can be used to predict the final dynamic instability(rockburst)are as follows:indicators such as the AE hit rate and AE count rate suddenly increase and then suddenly decrease;the AE hit rate exhibits a“quiet period”;during the“quiet period”,a small number of high-amplitude and low-frequency hits occur,and the signals corresponding to shear fracture continue to increase.The AE precursors for the final static instability(spalling)are as follows:both the AE hit rate and the b-value continuously decrease,and intermittent sudden increases appear in the high-frequency hits or the AE count rate. 展开更多
关键词 ROCKBURST slabbing SPALLING acoustic emission true triaxial test
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