快压缩P_(1)波在饱和冻土与弹性基岩分界面上的能量传输特性

Energy transfer characteristics of fast compressed P_(1) waves on interface between saturated frozen soil and elastic bedrock

基于弹性波在冻结饱和多孔介质与单相弹性介质中的传播理论,选取了饱和冻土中传播速度最大的快压缩P 1波入射在饱和冻土与弹性基岩分界面上的能量传输问题。根据分界面上的边界条件,推导出了快压缩P 1波从饱和冻土介质入射到弹性基岩分界面上透反射振幅比和能量率的解析表达式。研究了快压缩P_(1)波入射在饱和冻土与弹性基岩分界面上的能量与入射角度,入射频率,温度(含冰量),孔隙率,胶结参数以及接触参数的关系。研究结果表明:当入射角度为0°时仅存在压缩波,达到临界角后透射P波消失;各种波在达到临界角时出现不同程度的脉冲,其中反射P_(1)波最为显著;随着胶结参数,孔隙率,接触参数的增大,临界角越早出现;入射频率仅对反射P_(2),P_(3)和S_(2)波的能量反射率影响较大;当温度和含冰量较低或较高时,均不利于反射S_(2)波的能量产生。

Here,based on the propagation theory of elastic waves in frozen saturated porous media and single-phase elastic media,the energy transfer problem of fast compressed P_(1) wave with the highest propagation speed in saturated frozen soil incoming on interface between saturated frozen soil and elastic bedrock was selected for studying.Based on boundary conditions at the interface,analytical expressions for amplitude ratio and energy rate of transmission and reflection of fast compressed P_(1) waves incident on interface between saturated frozen soil media and elastic bedrock interface were derived.Relations of energy of fast compressed P_(1) waves incident on the interface with incident angle,incident frequency,temperature or ice content,porosity,bonding parameters and contact parameters were studied in detail.The results showed that when incident angle is 0,only compressed waves exist,and after reaching the critical angle,transmitted P waves disappear;various waves have different degrees of pulses when reaching the critical angle,in which reflected P_(1) wave is the most significant;with increase in bonding parameters,porosity and contact parameters,the critical angle appears earlier;incident frequency only has a larger impact on energy reflection rates of reflected P_(2),P_(3),and S_(2) waves;lower or higher temperature and ice content are not conducive to energy generation of reflected S_(2) wave.