The Application Of Radar Detect Technic In Structural Nondestructive Testing

In this paper, the theory of ground-penetrating radar used for nondestructive testing applied in civil engineering (NDT-CE) was studied on the basis of reading a lot articles about the nondestructive testing of concrete and ground-penetrating radar relevant information used in reinforced concrete structure. The arrangement of the paper is idea of linking theory with practice and theory to guide practice. Ground penetrating radar (GPR) forward program is maked by MATLAB code in this paper, and electricity of radar model about reinforced concrete was computed. The cracks echo signals in reinforced concrete was simulated, and through examples of GPR forward model echo signals of cracks in the reinforced concrete, the characteristics of horizontal, vertical and oblique direction cracks echo signal by the simulation model is studied. The theoretical calculation method of rebars diameter has been proposed in this paper. Following is the main content:(1) At first, importance of NDT-CE and development of GPR detects technic in structural non destructive testing are introduced in this paper.(2) The finite difference time domain (FDTD) method to perform simulation on the basis of Maxwell equation is adopted in this paper. FDTD method can obtaine satisfied result, which can guide the staff member processing structure explanation to the actually radar section. The writer has studied the numerical simulation method of GPR, introduced the main numerical simulation method. Currently, the research of GPR forward simulation is mainly concentrated in the geological model, there is little RC model forward simulation studies. In this paper, on the basic of reading a large number of literatures about electromagnetic waves and numerical simulation GPR forward, the author developed a computer program of Finite Difference Time Domain (FDTD) simulation by MATLAB, through this procedures, numerical simulation model of reinforced concrete had been done.(3) In addition, in this paper, theoretical calculation method of the bar diameter in GPR detection profile has been put forward, and the application of the theoretical calculation to the forward modeling profiles had been done to check the results, this theoretical calculation method, which is the preparation and foundation of reinforced concrete in the automatic calculation of the bar diameter provide methods and procedures. (4) The electromagnetic wave attenuation characteristics have been studied, and effective radar wave attenuation compensation method has been proposed. The attenuation compensation method has been applied to the actual testing profile, and which has achieved very good results.(5) The practical engineering example of GPR applied to industrial plant and basement floor of frame-shear wall structure testing.