单轴加载条件下瑞利波偏振和不同震相波速对应力敏感性的实验研究

The laboratory study on stress sensitivity of Rayleigh wave polarization and velocity of different seismic phases in rock under uni-axial

岩石应力状态的改变会使接收到的波形发生变化,这是利用弹性波检测介质性质和应力变化的基础。研究对应力敏感的弹性波参数及其分析方法对于发展介质应力监测技术具有重要意义。本文在实验室内以长方体花岗岩为样本,在不同的单轴压力下重复激发超声波且用三分量的传感器接收,利用记录的全波形信息研究了不同震相的到时、Rayleigh波偏振与岩石应力状态变化的关系。结果表明:①不同震相的波速对应力变化的敏感性为10-8/Pa数量级,且敏感程度从大到小依次为:Rayleigh波>S波>P波。②随着应力的增大,Rayleigh波偏振变强,但其敏感性随应力增大而变小,这反映出了介质性质的非线性变化特性。③应力较小时,Rayleigh波偏振对应力的敏感性比波速大数倍。

The change of the stress on rock leads to the variation of the wave passing through,which constitutes the base for the detection of the medium nature and the state of stress with elastic waves.It is significant for the development of the technology of monitoring stress to research the elastic wave parameter and its analytical method.We conducted a laboratory experiment,in which respective untrasonic were excited to pass through the marble and then received by a three-component sensor,aiming to make full use of the wave to study the variation of Rayleigh wave polarization and velocity of different seismic phases with the state of stress.It was found that：（1） the stress sensitivity of different seismic phase velocity is 10E-8/Pa,with a descending order：Rayleigh waveS waveP wave;（2） the larger the stress,the more intense the Rayleigh polarization,and the change is nonlinear;（3） the stress sensitivity of Rayleigh polarization is times greater than wave velocity.