关键词: 岩石破裂, 声波波速, 循环加载, 单轴加载, 波动理论

Abstract: Different rock samples were loaded up to explore the response characteristics of the acoustic wave velocity (AWV) in rock with stress changing. The testing results showed that the relationship between AWV and stress goes up linearly in the linear elastic load phase of granite and gneiss, and the relationship becomes nonlinearly quadratic if AWV comes up to its peak value and, finally, rock failure comes true if loaded further. As to the marble and sandstone, AWV keeps constant basically in the whole loading process. The AWV change in rock could be divided into two types according to the diagenesis of different rock, i.e., Type I: linear increasing-peak AWV-slow decreasing-abrupt decreasing (failure); Type II: keeping constant-abrupt decreasing (failure). It means that under cycling load AWV goes up linearly in elastic load phase then goes down abruptly if the load is increased to a certain extent and, further, rock failure happens. The reason why the AWV increases during elastic load phase is mainly due to density variation in rock samples. The process from initiation and propagation to breakdown of micro-cracks directly affects the rule of AWV change with stress.