几种无损检测技术在防渗墙质量检测中的应用

Application analysis of several non-destructive testing techniques in quality testing of impermeable walls

利用地质雷达、超声电视、视频电视和高密度弹性波CT等几种无损检测技术,对两个国家重点水利工程(西霞院反调节水库坝基和长江马鞍山河段一期防渗工程)的防渗墙进行了检测,通过对检测成果的分析,总结出每种无损检测技术在检测防渗墙中的优点及局限性:地质雷达检测防渗墙对内部缺陷情况可以进行定性解译,但定量测量不能满足要求;井下电视系统优点是通过超声波成像、视频成像,成果形象、直观可靠,但需要造孔;高密度弹性波CT检测防渗墙质量可反映墙体介质分布的均匀性,但目前软件只能满足一般性数据处理;超声波速CT成像技术能在不同深度位置将不同声速用不同颜色显示出来,成果一目了然,但图像颜色比较单一,相邻声速范围呈现的色彩区分较困难。

The impermeable walls of two state key projects of water conservancy in China, i.e. the Xixiayuan anti-regnlating reservoir dam foundation project and the first stage anti-seepage project of Maanshan section of the Yangtze River, were detected by use of several effective non-destructive testing methods, including the geological radar, ultrasonic television, video television, and high-density elastic wave CT. Through the analysis of the test results, the advantages and limitations of the above methods were summarized. The geological radar method could give a qualitative explanation of internal defects of impermeable walls, but it could not meet the testing requirement in quantitative measurement. The visualization and high reliability could be realized by the borehole TV system, but it is needed to drill boles. The high-density elastic wave CT detecting technique can reflect the homogeneity of wall materials, but the existing software can only be used to process the common data. The ultrasonic wave CT imaging technique could identify different depths by means of different sound velocities and express them with different colors, but the colors are relatively dull, and it is difficult to identify the boundaries of adjoining velocity ranges.