Acoustic Emission Characteristics of Red Sandstone Specimens Under Uniaxial Cyclic Loading and Unloading Compression
Acoustic Emission Characteristics of Red Sandstone Specimens Under Uniaxial Cyclic Loading and Unloading Compression
复制标题
单轴循环加卸载压缩下红砂岩试件的声发射特性
DOI：
10.1007/s00603-017-1389-6
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发表时间：
2018-04-01
影响因子：
6.2
通讯作者：
Chen, Yanlong
中科院分区：
文献类型：
--
作者：
Meng, Qingbin;Zhang, Mingwei;Chen, Yanlong
为探究周期性载荷作用下岩石材料变形破坏过程中的声发射特性，基于MTS 815岩石力学试验系统和AE21C声发射试验系统，进行了单轴循环加卸载压缩试验。建立了180个岩石试件在36种加载和卸载速率下的应力、应变、声发射活动、累积声发射活动与持续时间之间的关系。分析了加载和卸载阶段岩石应力-应变变化的声发射循环演化规律。揭示了岩石声发射活动的Kaiser效应和Felicity效应，并讨论了声发射事件规模显著增加对Felicity效应的影响。结果表明，声发射特征与岩石材料的应力-应变特性密切相关，受岩石内部微裂纹发育状态和程度的影响。如果应变大于零，则声发射事件发生在加载或卸载阶段。声发射活动的演化规律与岩石应变的变化一致。应变变形伴随着声发射活动，声发射事件的密度和强度直接反映了岩体的损伤程度。Kaiser效应存在于岩石材料的线弹性阶段，Felicity效应存在于塑性屈服和峰后破坏阶段，这两个阶段被弹性屈服强度所划分。该研究表明，确定AE活性显著增加所需的应激水平为其峰值应激的70% + 1。岩石试件的费利西蒂比值随加卸载循环次数的增加而减小。费利西蒂效应的周期大小和变化几乎是一致的，其中加载和卸载速率起微弱作用。
To explore the acoustic emission (AE) characteristics of rock materials during the deformation and failure process under periodic loads, a uniaxial cyclic loading and unloading compression experiment was conducted based on an MTS 815 rock mechanics test system and an AE21C acoustic emissions test system. The relationships among stress, strain, AE activity, accumulated AE activity and duration for 180 rock specimens under 36 loading and unloading rates were established. The cyclic AE evolutionary laws with rock stress–strain variation at loading and unloading stages were analyzed. The Kaiser and Felicity effects of rock AE activity were disclosed, and the impact of the significant increase in the scale of AE events on the Felicity effect was discussed. It was observed that the AE characteristics are closely related to the stress–strain properties of rock materials and that they are affected by the developmental state and degree of internal microcracks. AE events occur in either the loading or unloading stages if the strain is greater than zero. Evolutionary laws of AE activity agree with changes in rock strain. Strain deformation is accompanied by AE activity, and the density and intensity of AE events directly reflect the damage degree of the rock mass. The Kaiser effect exists in the linear elastic stage of rock material, and the Felicity effect is effective in the plastic yield and post-peak failure stages, which are divided by the elastic yield strength. This study suggests that the stress level needed to determine a significant increase in AE activity was 70% of thei+ 1 peak stress. The Felicity ratio of rock specimens decreases with the growth of loading–unloading cycles. The cycle magnitude and variation of the Felicity effect, in which loading and unloading rates play a weak role, are almost consistent.