多孔介质中水位变化对波形、波速和波谱影响的实验研究

为了研究地下水和地震波之间的关系，设计了一套水位实验装置，用注水方法研究了多孔介质中水位变化对P波和S波的波速、波形和波谱的影响。实验结果表明：波垂直水面传播时，速度与时间平均方程的结果基本一致；波平行水面传播时，虽有叠加效应但并非简单的叠加。从干燥到注满水，P波速度明显增大，波幅和波谱能量显下降，主频明显降低；在接近注满水时，出现特殊的高频初至小波，而S波速度略有减小 ，波幅和波谱能量则一般是先降后升，主频基本没有变化。比较了注子和饱水的不同，并引入三相气体包裹体模型进行了解释。

A Laboratory Study of Influence of Variation in Water L evel on Velocity，Waveform and Spectrum in Porous Medium

In order to study relation between groundwater and seismic wave,a set of water level test device is designed and the influence of variation in water level on velocity,waveform and spectrum in porous medium using water injection is studied.The results show that velocity agrees on the whole Wyllie equation as wave propagates perpendicularly to water surface;waves aren't simply superposed as they propagate in parallel with water surface.From dryness to full level,the P wave velocity obviously increases,and its amplitude,energy and center frequency distinctly decrease,and a special primary wave with high frequency and low amplitude turns out at near full level.The S wave velocity decrease slightly,and generally,first,its amplitude and energy decrease,then increase,and its center frequency remains the same.Injection is compared with saturation and a gas pocket model is introduced to explain the results.