Impacts of Cyclic Loading and Unloading Rates on Acoustic Emission Evolution and Felicity Effect of Instable Rock Mass
Impacts of Cyclic Loading and Unloading Rates on Acoustic Emission Evolution and Felicity Effect of Instable Rock Mass
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循环加卸载速率对不稳定岩体声发射演化及幸福效应的影响
DOI：
10.1155/2018/8365396
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发表时间：
2018
影响因子：
--
通讯作者：
Zhang Nong
中科院分区：
文献类型：
--
作者：
Zhang Mingwei;Meng Qingbin;Liu Shengdong;Qian Deyu;Zhang Nong
在联合试验台上进行了6种加载速率和6种卸载速率方案的单轴循环加卸载压缩试验。揭示了加载和卸载速率对岩石声发射特性的影响。结果表明：随着加载和卸载速率的增大，整个岩石变形破坏过程中声发射环总数减小；在同一周期内，增加加载速率使加载阶段声发射环减小，增加卸载速率使卸载阶段声发射环减小。总声发射计数与加载和卸载速率呈负线性关系。加载阶段是声发射现象的活跃期，加载速率对声发射特征的影响更为明显。尤其当加载速率大于2.0 kN/s时，岩石试件脆性破坏较为明显。循环荷载达到单轴抗压强度的1/3 ~ 1/2倍后，岩石费利西蒂效应更加明显。随着加载速率的增加，弹性阶段费利西蒂比值减小，塑性阶段略有增加，而随着卸载速率的增加，弹性阶段费利西蒂比值逐渐减小，塑性阶段费利西蒂比值基本保持不变。
Uniaxial cyclic loading-unloading compression experiments with schemes of six loading rates and six unloading rates were carried out on the combined testing platform. Impact of loading and unloading rates on rock AE characteristics was revealed. Results show that increasing loading and unloading rates resulted in decreasing total AE rings in the entire rock deformation and failure process. Increasing loading rate decreased the AE rings at loading stages, and increasing unloading rate decreased the AE rings at unloading stages in the same cycle. Total AE counts had a negative linear relationship to the loading and unloading rates. The loading stage was the active period of the AE phenomena, and impacts of the loading rate on the AE characteristics were more apparent. Especially when the loading rate was greater than 2.0 kN/s, brittle failure of rock specimens became noticeable. After the cyclic load reached the uniaxial compressive strength of 1/3∼ 1/2 times, the rock Felicity effect became more obvious. With the increase of the loading rate, the Felicity ratio decreased in the elastic stage and increased a little in the plastic stage, whereas with the increase of the unloading rate, the Felicity ratio decreased gradually in the elastic stage and remained almost the same in the plastic stage.