Abstract: An experimental study on the travel time, magnitude and attenuation characteristics of elastic wave propagating along σ₂(x direction)and σ₃(y direction) in marble specimen has been carried out using a true triaxial(σ₁>σ₂>σ₃) compression apparatus. With increasing stress the travel time t and magnitude A of the first peak of P wave decrease, on the contrary while along the y direction it gives a completely opposite result. Starting from 95% of failure strength along both directions t increases rapidly, but A decreases and the attenuation coefficient K of wave magnitude also decreases. This phenomenon is considered as a characteristic change of the fracturing forerunners under true triaxial compression. For the I way of applying stress to the specimen the differential stress at the moment of rapid increase of t value is lower than that for the I way.

Key words: True triaxial compression, Elastic wave, Stress

摘要： 在σ₁>σ₂>σ₃的真三轴压缩试验机上进行了弹性波在大理岩试件中传播时沿σ₂(x方向)和σ₃(y方向)的走时、幅值及衰减特性的实验研究。随着载荷应力增加,在x方向上,P波第一个波峰的走时t减小,幅值A减小;在y方向则相反。大约从破坏应力的95%开始,两个方向上t又都迅速增加,A减小,波列振幅衰减系数K也减小,这是真三轴压缩情况下的一种破裂前兆变化特征。Ⅰ型应力途径t开始迅速增加时的差应力值低于Ⅱ型。

关键词: 真三轴压缩, 弹性波, 应力