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本文在分析前人研究成果的基础上,建立了岩石试件双轴加载超声波衰减测试系统,编制了数据处理用的程序。作者用脉冲传播频谱比方法,对砂岩和辉绿岩试件进行了声波衰减与应力关系的实验研究,通过近百次实验,取得了一些有价值的数据。 实验结果表明,在双轴压缩下,Q值随差应力的变化规律,不同于单轴压缩下或静水压力下,Q值的变化规律。在一定的侧压力下,声衰减的Q值随主应力增加而迅速增加,到一定压力后,Q值反而略有下阵,直至极限应力时,Q值趋于稳定值。另外,随恻向应力的增加,Q值随主应力增加而增加的幅度逐渐变小。对不同的岩石Q值随差应力的变化率与岩石种类、孔隙率和饱水度有关。 本文介绍的声衰减测量方法,可以在岩体工程的应力测试和岩石力学研究中推广应用。
Based on the analysis of the previous research results, this paper established a biaxial loading ultrasonic attenuation test system for rock specimens, and developed a program for data processing. The authors used the pulse-spread spectrum ratio method to experimentally study the relationship between sound attenuation and stress attenuation of sandstone and diabase samples. Some valuable data were obtained through nearly one hundred experiments. The experimental results show that under the biaxial compression, the Q value changes with the difference stress, which is different from the Q value under the uniaxial compression or hydrostatic pressure. At a certain lateral pressure, the Q value of sound attenuation increases rapidly with the increase of the principal stress. After reaching a certain pressure, the Q value will be slightly lower, and the Q value tends to be stable until the ultimate stress. In addition, as the stress increases, the amplitude of Q increases with the increase of principal stress. The rate of change of Q value with different stresses to different rocks is related to rock type, porosity and water saturation. The acoustic attenuation measurement method introduced in this paper can be applied in the stress testing and rock mechanics research of rock mass engineering.