三轴压缩下煤样的声发射及分形特征研究

ACOUSTIC EMISSION AND FRACTAL CHARACTERISTICS OF COAL ROCK SAMPLES UNDER TRIAXIAL COMPRESSION

  • 摘要: 为了研究煤样在不同围压下的声发射及分形特征,利用RMT-150C 型岩石力学伺服试验系统和CDAE-1 型声发射检测仪对煤样试样在不同围压(5MPa,10MPa,15MPa) 进行了实验研究. 对煤样试样的声发射计数和累计计数以及声发射序列的分形特征进行了对比研究. 研究结果表明:不同围压下煤样的声发射特性具有一定的差异性,围压越高前兆信息越明显. 不同围压下煤样都具有分形特征,随着围压的增大,分形特征有所增强. 煤样在失稳破坏过程中声发射序列的分形维值都会出现一个波动-上升-突降的过程,提出可以作为煤样体失稳破坏的前兆信息.

     

    Abstract: In order to study the acoustic emission and the fractal characteristics of coal samples under triaxial compression, experiments were carried out by using the RMT-150C rock mechanics test system and the CDAE-1 acoustic emission instrument under different confining pressure(5MPa, 10MPa, 15MPa), and the acoustic emission count, the cumulative count and the acoustic emission sequence fractal characteristics of coal sample were obtained. It is shown that the coal has different acoustic emission characteristics under different confining pressures, the higher the confining pressure is, the more precursor information will be obtained. The coal samples show the fractal characteristics under different confining pressures, and the fractal characteristics will strength with the increase of the confining pressure. The acoustic emission sequence fractal dimension value will experience a process of volatility-rise-drop during the process of coal sample failure, which can be regarded as the precursor information to predict the collapse of the coal rock masses.

     

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