多孔介质中水位变化对波形、波速和波谱影响的实验研究

摘要

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 l evel 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 w ave 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 w ave velocity obviously increases,and its amplitude,energy and center frequency d istinctly decrease,and a special primary wave with high frequency and low amplit ude turns out at near full level.The S wave velocity decrease slightly,and gener ally,first,its amplitude and energy decrease,then increase,and its center freque ncy remains the same.Injection is compared with saturation and a gas pocket mode l is introduced to explain the results.%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 谱能量显著下降，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。比较了注水和饱水的不 同，并引入三相气体包裹体模型进行了解释。