The Application And Study Of FDTD Modeling Method In The Engineering Testing With GPR

Geological radar is another name of ground penetrating radar; it is a tool toidentify subsurface media distribution through electromagnetic waves from106-109Hz by way of geophysical methods. The method is mainly applied to thedetection of dam body, highway, railway tunnel testing, also it could be applied tothe engineering investigation and urban pipeline detection and so on. Through manytimes tunnel testing work the author realized that how to interpret the radar imagesaccurately is the key for this method. Therefore, the main research target of thispaper is guiding the interpretation of the radar images by the electromagnetic FDTDmodeling technology.The basis of this article is the working principle of GPR and the forwardmodeling technology of the finite difference time domain. A lot of defect structuresmay be generated in the tunnel could be created firstly, especially for geometricmodels with more complicated defects, such as continuation steel grid、void and voidbehind the steel grid and so on, then radar wave reflection profile maps could beobtained by GPRmax2D and drawing software. Through contrasting the actuallyradar images with modeling images and analyzing the similarities and differencesbetween the two radar signals, the effectiveness of this method will be proved by theexcavation of the targets.