不同应力路径大理岩声发射破坏前兆的试验研究

发布时间：2018-03-04 13:56

本文选题：声发射　切入点：应力路径　出处：《岩土工程学报》2016年07期 　论文类型：期刊论文

【摘要】：应力路径不同,岩石变形和破坏过程中伴随的声发射特征也不同,通过不同路径大理岩加、卸荷试验,结合分形维数原理,探讨声发射破坏前兆随应力路径的变化规律。试验结果表明:1岩样破坏处的声发射计数率和破坏前的累计计数率增长率由大变小的应力路径为加轴压卸围压、恒轴压卸围压、单轴、常规三轴路径。2常规三轴路径下岩样临近破坏时,声发射事件计数率存在明显的"低声发射期",围压越大,声发射前兆"低声发射期"越明显;同时累计振铃计数率增长速率降低的拐点出现后很短时间,岩样也会发生破坏。3低围压下恒轴压、卸围压路径岩样破坏时累计振铃计数率的增长速率近似为切线。加轴压、卸围压岩样破坏前一段相近计数率后存在声发射计数率的"平静期",围压增加,"平静期"持续时间增加,岩样破坏产生的计数率越高。4在低围压应力环境下应力比0.8、高围压应力环境下时间比0.4时声发射分维数降低的特征可以作为岩样的破坏前兆分析。
[Abstract]:Different stress paths lead to different acoustic emission characteristics in the process of rock deformation and failure. Through the loading and unloading tests of marble with different paths, the principle of fractal dimension is combined. The variation of AE precursor with stress path is discussed. The experimental results show that the counting rate of AE and the increase rate of accumulative counting rate before failure are increased from large to small, and the stress paths are axial pressure relief, constant axial pressure relief, and constant axial pressure release, respectively, and the experimental results show that the calculation rate of acoustic emission and the rate of increase of cumulative counting rate before failure are increased from large to small. Under uniaxial, conventional triaxial path .2 when rock samples under conventional triaxial path approach failure, the acoustic emission event counting rate has obvious "low emission period", the larger the confining pressure is, the more obvious is the sound emission precursor "low emission period"; At the same time, a short time after the inflection point at which the cumulative ringing counting rate decreases, the rock samples will also have damage .3 under constant axial pressure under low confining pressure, and the growth rate of cumulative ringing counting rate will approximate to tangent line and axial pressure when the rock sample is destroyed by unloading the confining pressure path. There is a "quiet period" of acoustic emission counting rate after the sample of unloaded confining pressure destroys the near counting rate in the previous section, the confining pressure increases, and the "quiet period" continues to increase. The higher the counting rate of rock sample is, the higher the stress ratio is 0.8 under low confining pressure stress, and the lower the fractal dimension of acoustic emission under high confining pressure stress is 0.4, which can be used as the precursor analysis of rock sample failure.
【作者单位】：中国科学院武汉岩土力学研究所;青岛理工大学理学院;后勤工程学院建筑工程系;
【基金】：国家自然科学基金项目(11232024,41372298,41320104005,41472270) 中国博士后科学基金项目(2015M572232)
【分类号】：TU45

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