The Media Defect Detection Model Experiments Research In The Case Of Complex Interference

With the wide application of the ground penetrating radar in nondestructivetesting, domestic and foreign scholars have carried out in-depth study on the theoryand application of ground penetrating radar,but rarely on the GPR detecting defectmodel experiments in the case of complex interference which were analyzed andstudied in this paper. Fully considering the practical application of engineering in theprocess of model design, all kinds of interference and defect were designed to detectand scan on the basis of referencing a large number of filling medium and concretemedium defect model experiment and learning the basic theory of ground penetratingradar.The propagation characteristics of electromagnetic wave and the electromagneticproperties of the medium are the theoretical core of GPR. In the process ofelectromagnetic wave propagation，with the change of the electromagnetic propertiesof the media, the phenomenon of reflection,refraction and diffraction will beproduced，which not only provides a basis for identifying the target defects， but alsoproduces complex interference signal. By designing physical defect modelexperiments in different interference, shapes, sizes and depth,the radar scanned imageof defects in the concrete and the filling soil in the case of complex interference wasanalyzed to acquire the impact of the interference on the media defect detection. Twotypes of ground penetrating radar were available to conduct the study of defect modelexperiment, which are IDS-K2and LTD-2100. Model is divided into three tyeps:(1)To detect double steel mesh in the concrete slab in the case of complex interferencewith the600MHz and1600MHz antenna;(2) To detect the holes in the filling soil inthe case of complex interference with400MHz,600MHz and900MHz;(3) To detectthe holes and crack in the concrete in the case of complex interference with400MHzand900MHz.Through analyzing and comparing the scanned images of the models, theradar antenna parameters of different media,the design of measuring line layout, thesteps of data processing,the method of image interpretation and the image features oftypical defects were summarized to provide the basis of antenna frequency selectionand defect interpretation for engineering testing.By two engineering examples thecapability of the ground penetrating radar to detect defects was validated well.