Abstract

The acoustic emission of hollow plate specimens of two calcitic marbles quarried in Greece is studied in the laboratory under uniaxial compression. Theses plate specimens are used as physical models, having a cylindrical opening of various sizes in the middle. Location analysis of the acoustic emission sources follows closely the macroscopic fracture surfaces, observed inside the collapsed physical models after the end of the experiments. The located AE signals’ sources are determined as either tensile or shear, according to the average frequency AF–RA value analysis. It is found that tensile AE signals’ sources dominate during fracturing of the studied physical models, from the onset of the fracturing development to their maximum strength. The overall percentage of the signals attributed to tensile AE sources is of the order of 90%, while most of the located shear AE sources are nucleated after the sidewall’s rock failure. The potential of the acoustic emission technique stands out, as it is capable to distinguish the tensile or shear nature of the recorded AE signals, and to locate reliably the microcracking of such hollow specimens during the compression tests, at least for the currently studied marble varieties.

Article Highlights

• AE location analysis is performable on hollow marble specimens in simple compression.

• The nature of the marble’s microcracking is distinguishable by the AF–RA value analysis.

• The marbles’ fracturing process is studied through 3D AE location in distinct time/test-steps.

中文翻译：

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单轴压缩钙质大理石空心板的声发射位置分析和微裂纹性质确定

摘要

在单轴压缩下，在实验室研究了在希腊开采的两块钙质大理石的中空板标本的声发射。这些板状样品用作物理模型，中间具有各种尺寸的圆柱形开口。实验结束后，在塌陷的物理模型内部观察到声发射源的位置分析紧密遵循宏观断裂表面。根据平均频率AF-RA值分析，定位的AE信号源确定为拉伸或剪切。研究发现，从断裂发展到最大强度，拉伸AE信号源在断裂过程中占主导地位。归因于拉伸声发射源的信号的总百分比约为90％，而大多数定位的剪切AE源在侧壁岩石破裂后成核。声发射技术的潜力突出，因为它能够区分所记录的声发射信号的拉伸或剪切性质，并且至少在当前研究的大理石品种中，能够在压缩测试过程中可靠地定位此类中空样品的微裂纹。 。

文章重点

• AE位置分析可以在简单压缩的情况下对空心大理石标本进行。

• 大理石的微裂纹的性质可以通过AF-RA值分析来区分。

• 通过在不同的时间/测试步骤中通过3D AE位置研究大理石的破裂过程。