基于超声波原理的防渗层渗漏定位模型研究

Ultrasonic monitoring method of anti-seepage layer

为解决运营前垃圾填埋场防渗层渗漏定位问题,提出了基于超声波散射特性的高密度聚乙烯(High Density Polyethylene,HDPE)膜渗漏检测方法。根据超声波通过渗漏位置发生散射导致能量衰减的特性,利用小波分析提取有无渗漏时超声波能量密度参数,依据两种状态下参数定义损伤指数,结合损伤成像实现对HDPE膜渗漏位置定位。实验通过压电片铺设在HDPE膜表面形成检测网络,任意波形发生器控制压电片产生特定超声波信号,采用一发多收方式对检测区域进行扫描。实验结果表明:HDPE膜有、无渗漏的损伤指数至少相差100倍,差异明显。实验实现了模拟渗漏的定位,单渗漏点的最大定位误差为8.4 mm,双渗漏点最大定位误差为13.7 mm,定位误差在可接受范围内。

In order to solve the problem of leakage localization of anti-seepage layer in landfill before operation,an ultrasonic leakage detection method of high density polyethylene(HDPE)membrane is proposed.According to the characteristics of energy attenuation caused by the ultrasonic wave scattering at the leakage location,the wavelet analysis is used to extract the ultrasonic energy density parameters with or without leakage.The damage index is defined according to the parameters in the two states,and the leakage location of HDPE film is determined by combining damage imaging.In the experiment,a detection network is formed by the piezoelectric plate laid on the surface of HDPE film,and the piezoelectric plate is controlled by any waveform generator to generate specific ultrasonic signal.The detection area is scanned by the way of“one emitting and multiple receiving”.The experimental results show that the damage index of HDPE membrane with or without leakage has a difference of at least 100 times.The localization of simulated leakage is realized.The maximum localization error of single leakage point is 8.4mm,and the maximum localization error of double leakage points is 13.7 mm.The localization error is within the acceptable range.