论文部分内容阅读
利用岩石声波-声发射一体化测试系统与应力加载装置,系统地研究了三轴压缩试验中盐岩的变形破坏特征与声波声发射活动规律。结果表明:(1)三轴加载试验中,盐岩的破坏过程分为压密与弹性压缩阶段、裂纹产生与稳定增长阶段、裂纹加速增长阶段和应变硬化阶段。阶段Ⅰ中,盐岩纵横波波速略微上升,并伴随少量的声发射事件;阶段Ⅱ中,盐岩的声发射活动开始活跃,超声波波速稳定;阶段Ⅲ和阶段Ⅳ中,岩石的声发射事件数量大幅度上升,纵波波速保持稳定,横波波速呈现明显地下降趋势。(2)盐岩的声波与声发射特征与试验围压应力密切相关。围压水平越低,受载盐岩破坏过程中的波速变化率越大;围压水平越高,盐岩超声波波速变化率越小。根据对试验数据的分析,当盐岩轴向应变达到10%,围压条件为5、10、15、20 MPa时盐岩的声发射事件数量分别为16 271、8 764、3 041、906个,围压对盐岩破坏过程的声发射活动有较大的影响,显示了围压致密效应。
By using rock acoustic-acoustic integrated testing system and stress loading device, the deformation and failure characteristics of rock salt and the law of sound wave emission in triaxial compression tests are studied systematically. The results show that: (1) In the triaxial loading test, the failure process of salt rock is divided into compaction and elastic compression stage, crack growth and steady growth stage, crack growth and strain hardening stage. In Stage I, the wave velocity of S-wave in salt rock increased slightly accompanied by a small amount of AE events; in Stage II, the acoustic emission activity of rock salt started to be active and the velocity of ultrasonic wave was stable; in Stage III and IV, the acoustic emission events The wave velocity of P-wave keeps stable and the wave velocity of S-wave shows a clear downward trend. (2) The characteristics of acoustic and acoustic emission of salt rock are closely related to the test confining stress. The lower the confining pressure is, the larger the rate of change of wave velocity during the destruction of salt rock is. The higher the confining pressure is, the lower the rate of change of ultrasonic wave velocity is. According to the analysis of experimental data, the acoustic emission events of salt rock are 16 271, 8 764, 3 041 and 906 respectively when the axial strain of salt rock reaches 10% and the confining pressure is 5, 10, 15 and 20 MPa , Confining pressure has a greater impact on the acoustic emission activity of salt rock failure process, showing confining pressure compact effect.