大理岩的剪切波分裂对差应力变化响应的实验研究

EXPERIMENTAL STUDIES OF MARBLES ON RESPONSE OF SHEAR-WAVE SPLITTING TO DIFFERENTIAL STRESS VARIATION

利用ＤＺ９５型多通道瞬态波形记录仪和ＧＣ－１００型工程多波参数分析仪，对山东莱州大理岩进行了剪切波分裂观测研究．通过两组岩样的测量，在带有自然优势定向排列裂缝的岩样在无加载状态下发现剪切波的分裂现象，而带有优势层理走向的完整岩石则在加载到一定程度下才能观测到剪切波的分裂．随着载荷的增加，多数岩样在临近破坏时都记录到剪切波分裂的时间延迟有一个迅速的抬升，但抬升之前的变化过程不同，不同位置的观测结果也大不相同．实验还发现，在一定压力下，即使载荷保持不变或卸载一加载，岩石中剪切波分裂的时间延迟仍然增加，我们称之为“惯性生长”．在实验中，还少量地记录到一些声发射事件，和人工源的效果一样，也可在接收波形中清楚地分辨出剪切波的分裂．

Using DZ95 multi-channel instananeous waveform recorder and GC-100engineering multiple wave parameter analytical instrument the shear-wave splitting isobserved and studied for Laizhou marbles of Shandong of China are With theincrement of loading, the splitting of shear-wave takes place and the time delay ofshear-wave splitting will change obviously. In most specimens, time delay increasesquickly just before it is destroyed. The phenomena are different at different specimenand different azimuth. Sometime the time delay falls down before it increases. Undersome pressure, time delay also increases when the level of press keeps even unloading.This kind of phenomenon is called 'Inertia Development'. In this experiment someevents of acoustic emission are also recorded, and the shear-wave splitting can also beobserved clearly, as those from the man made source emission.