A Comparative Evaluation of Stress-Strain and Acoustic Emission Methods for Quantitative Damage Assessments of Brittle Rock
A Comparative Evaluation of Stress-Strain and Acoustic Emission Methods for Quantitative Damage Assessments of Brittle Rock
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DOI：
10.1007/s00603-014-0590-0
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发表时间：
2015-03-01
影响因子：
6.2
通讯作者：
Cho, Gye-Chun
中科院分区：
文献类型：
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作者：
Kim, Jin-Seop;Lee, Kyung-Soo;Cho, Gye-Chun
本研究的目的是确定韩国原子能研究所地下研究隧道（KURT）花岗岩的裂纹起裂和损伤应力阈值。在此基础上，利用裂纹体应变、b值、矩张量损伤参数、声发射能量等多种方法推导出损伤的定量演化过程。进行单轴压缩试验，同时记录应力应变和声发射活动。应力水平为0.42 ~ 0.53 σ (c)时出现裂纹起裂阈值，应力水平为0.62 ~ 0.84 σ (c)时出现裂纹损伤阈值。假设损伤累积超过裂纹起裂应力阈值，由损伤参数推断出KURT花岗岩在各应力水平下的归一化完整性。应力水平为0.84 σ (c)时，裂纹体积应变与声发射方法的最大偏差为16.0%。利用机械测量的应力-应变关系（裂纹体积应变）成功地将KURT花岗岩的损伤参数与物理检测的声发射波的损伤参数进行了关联和比较。通过对损伤识别和损伤量化方法的综合比较，从实际现场适用性和得到的损伤值的可靠性角度出发，建议采用声发射能量法进行损伤估计。
The purpose of this study is to identify the crack initiation and damage stress thresholds of granite from the Korea atomic energy research institute's Underground Research Tunnel (KURT). From this, a quantitative damage evolution was inferred using various methods, including the crack volumetric strain, b value, the damage parameter from the moment tensor, and the acoustic emission (AE) energy. Uniaxial compression tests were conducted, during which both the stress-strain and AE activity were recorded simultaneously. The crack initiation threshold was found at a stress level of 0.42-0.53 sigma (c), and the crack damage threshold was identified at 0.62-0.84 sigma (c). The normalized integrity of KURT granite was inferred at each stress level from the damage parameter by assuming that the damage is accumulated beyond the crack initiation stress threshold. The maximum deviation between the crack volumetric strain and the AE method was 16.0 %, which was noted at a stress level of 0.84 sigma (c). The damage parameters of KURT granite derived from a mechanically measured stress-strain relationship (crack volumetric strain) were successfully related and compared to those derived from physically detected acoustic emission waves. From a comprehensive comparison of damage identification and quantification methods, it was finally suggested that damage estimations using the AE energy method are preferred from the perspectives of practical field applicability and the reliability of the obtained damage values.