不同岩石声发射活动特性的实验研究

Experimental Study on AE Activity Characteristics of Different Rock Samples

应用声发射及其定位技术,对不同岩样破裂过程的声发射活动规律进行实验研究,借以揭示不同岩样的破裂失稳机理.实验结果表明:几种岩石的破坏模式相同,均发生劈裂破坏;在相同实验条件下,在初始加载时,5种岩样产生的声发射事件均比较少;随着载荷的增加,不同岩石的声发射活动表现并非一致,砂岩在整个加载过程产生的声发射事件数最少,而花岗岩产生的声发射事件数最多;砂岩和花岗岩(红色)其声发射事件变化率非常明显,在破坏前无任何征兆;由于声发射事件定位是时差定位法,岩样波速影响着声发射事件的定位,砂岩、大理岩(黑色)及花岗岩(红色)等岩样没有得到定位结果;而花岗岩与大理岩的声发射定位结果,直观反映了其内部裂纹初始、扩展和贯通过程;因而,声发射活动与岩石的本身属性是直接相关的.

To reveal the failure/instability mechanism of different rock samples, the acoustic emission （ AE ） and its location functioning was applied to studing on the rock failure process under uniaxial compression and what role the AE plays in it. The results showed that failure modes of all samples are the same, i.e. , the split failure, and the AE functioning to those five kinds of rock samples differs from each other with load increasing under otherwise equal conditions, though their accumulative AE events are similarly few during initial loading step. During loading, the number of AE events is minimum in sandy rock but maximum in granite, and both the numbers in sandy rock and red granite change very clearly with no portent of failure to come. The AE location as a time-of-arrival results are affected by the elastic wave velocity in rock sample. It was found that AE location is unavailable to the samples of sandy rock, black marble and red granite but available to the samples of marble from Dandong and granite from Jinzhou indicating visually the formation and propagation of a crack and how it runs though. A conclusion is thus drawn that AE location functioning relates directly to the attributes of rock samples.