不同应力路径下盐岩破坏声发射时序特征研究

利用RMT-150B岩石力学多功能系统和声发射监测系统,对不同应力路径下的盐岩破坏过程进行试验研究。在试验结果基础上,分析了盐岩常规单轴加载、分级加卸载和多级加载过程中的声发射时序特征和变形特征。试验表明:盐岩常规单轴加载变形表现明显的阶段性特征,声发射信号阶段性特征也比较明显;分级加卸载试验中,存在比较明显的记忆效应,在低应力水平有较明显的声发射Kaiser效应,而在70%峰值应力卸载再加载时,则出现Felicity效应;多级加载试验表明,在低应力水平稳压对盐岩造成的损伤不大,很少有新生裂纹;而在高应力水平稳压时,会有大量由新生微裂纹和裂纹扩展产生的声发射事件。

Study of Acoustic Emission Timing Features of Salt Rock Subjected to Different Stress Path Loadings

Damage process of salt rock subjected to different stress path loadings was experimentally investigated by using RMT-150B rock mechanics multi-function systems and acoustic emission monitoring system. Based on experimental results, acoustic emission timing characteristics and deformation features of salt rock subjected to conventional uniaxial loading, step loading-unloading and multi-stage loading respectively were analyzed. Experiments indicate that acoustic emission signal and deformation of salt rock under conventional uniaxial loading present obvious stage characteristics. In step loading-unloading experiment, memory effect is obvious. At lower level stress, Kaiser effect of acoustic emission is obvious; When at 70% peak stress level reloading after unloading, Felicity effect of acoustic emission occurs. Multi-stage loading experiments show that at lower level stress, stable load causes only small damage of salt rock, there are few new cracks. But at higher level stress, stable load causes acoustic emission due to large amount of newly produced cracks and crack propagation.