基于超声横波的混凝土结构无损检测数据成像技术

目前超声波成像主要采用合成孔径聚焦技术(SAFT),成像质量很大程度上依赖于超声波速估计的准确性和噪声压制的效果。超声波和地震波在固体介质中的传播特征具有相似性,故基于成熟的地震数据处理技术,建立了一套适用于商用超声横波反射检测仪的数据成像处理方法。基于炮检互易定理,对仪器的单边观测数据进行重构而转换为双边观测数据,再对双边观测数据采用地震数据处理中的多次叠加和克希霍夫偏移技术进行成像。大型混凝土道床模型应用案例表明,提出的成像技术完全适用于商用超声横波检测仪的数据成像,与仪器配套的国外商业合成孔径聚焦技术成像结果相比,成像分辨率有明显改善,并对混凝土层位界面和内部钢筋结构的反应更为精细。

Nondestructive testing data imaging technology of concrete structures based on ultrasonic shear wave

Currently,synthetic aperture focusing(SAFT)is the main method of ultrasonic imaging.The imaging quality of SAFT depends greatly on the accuracy of ultrasonic velocity estimation and the effect of noise suppression.Since the propagation of ultrasonic wave in concrete medium is similar to that of seismic wave in underground medium,we established a set of data processing procedure applied to the commercial ultrasonic shear wave detector based on the seismic data processing technology.According to the reciprocity principle,we transformed the single-ended spread record of ultrasonic detector into the artificial split spread record,and carried out multiple stacking technique and Kirchhoff migration technique to image the ultrasonic data.Concrete bed model tests show that the proposed imaging technique is suitable for data imaging of commercial ultrasonic shear detector,and can significantly improve the imaging resolution and identify concrete layered interfaces and internal reinforced structures more precisely than the ultrasonic detector′s built-in synthetic aperture focusing imaging results.