孔隙介质渗流过程诱发声发射信号特征研究

Characteristics of Acoustic Emission Signals Induced by Seepage Process in Porous Media

在不破坏结构情况下,利用声发射(AE)监测技术探究不同流速下间断级配颗粒介质运动规律,以及孔隙渗流过程声发射信号变化规律。通过渗流过程中由小颗粒介质位移产生的声发射信号和PIV技术相结合进行分析。结果表明:小颗粒介质数量一定时,流速较大的试验组AE事件数更多,即振铃计数更大、频谱重心更高;水流量相近时,试验中小颗粒介质含量直接影响AE事件数量,即含砂量较大的试验组AE事件数更多;含有小颗粒介质情况下,水流量越大小颗粒运动速度越快同时AE初始信号强度越大。研究表明:声发射监测技术能较好地反映孔隙渗流中颗粒介质的运动,为孔隙介质渗流过程中的小颗粒搬运监测和堤坝管涌预警提供一定的研究基础。

Without destroying the structure,the acoustic emission(AE)monitoring technology was used to explore the motion law of gap grading particle media at different flow rates,and to reveal the characteristic law of acoustic emission signals in the process of pore seepage.The analysis was carried out by combining the acoustic emission signal generated by the displacement of the small particle medium during the seepage process with the PIV technique.The results show that:when the number of small⁃particle media is constant,the experimental group with higher flow velocity has more AE events,that is,the ringing count is larger and the spectrum center of gravity is higher,when the water flow rate is similar,the content of small⁃particle media in the experiment directly affects the number of AE events.That is,the experimental group with larger sand content has more AE events;in the case of medium with small particles,the larger the water flow rate,the faster the particle movement speed and the greater the initial signal intensity of AE.The above studies show that the acoustic emission detection techn ology can better reflect the movement of granular media in pore seepage,and provide a certain research basis for small particle transport mo⁃nitoring and dam piping early warning in the process of pore media seepage.