单轴压缩下砂岩的P波动力学特征的实验研究

THE EXPERIMENTAL STUDY ON P WAVE KINETIC CHARACTERISTICS OF SANDSTONE UNDER UNIAXIAL COMPRESSION

摘要:

本文详细介绍了在单轴压缩下砂岩的P波动力学特征的实验结果。有关的动力学特征参数包括:振幅、振动持续时间、振幅谱、尾波走时持续时间及衰减系数α。观测了水对这些参数的影响。
主要实验结果如下:
1.扩容后压力的增加将使通过岩石标本的P波最大振幅和振动持续时间增加。
2.压力的增加将使P波振幅谱中的低频分量增加。
3.水对P波动力学特征的影响是十分显著的,它将使P波振幅减小,振幅谱中的高频分量减少。
4.压力的增加将使P波尾波持续数时间增长,衰减系数α减小。
主要实验结果和理论分析、野外观测结果比较一致。这对于探讨地震波动力学特征的前兆异常是有益的。

Abstract:

In this paper, the experimental results on P wave kinetic characteristics of sandstone under uniaxial compression are particularly introduced. Th kinetic parameters include the amplitude, the vibration continuous time, the amplitude spectrum, the coda trail continuous time and the attenuation coeffieient.The effect of water on these parameteres has been studied. The results are:
1. The maximum amplitude and the vibration continuous time were increased with the compression increase, both quickly decreased near the extreme failure.
2. The low frequncy compsition in P wave amplitude spectrum was increased with the compression increase.
3. The P wave kinetic characteristics were greatly affected by water. The existence of water decreases P wave amplitude and high frequency composition of amplitude spectrum.
4. The coda continuous time was increased and the attenuation coefficient was decreased with the compression increase.
Chief results in the experiment and their theoretical analysis are in agreement with the results observed in field-work.
These results would be of advantage to the discussion of precursor anomaly on kinetic characteristics of the seismic wave.