Forward simulation of ground penetrating radar used in semi-rigid base cracking detection

摘要

In this paper, the Two-Dimension Finite Difference Time Domain (2D-FDTD) equations of Ground Penetrating Radar (GPR) electromagnetic wave, which propagates in pavements, are briefly established. And the electromagnetic wave of the air-coupled antenna GPR and ground-coupled antenna GPR which propagates in the pavements with semi-rigid base cracking is simulated by using the 2D-FDFD method. The simulation results indicate that a negative reflected wave appears between the positive reflected wave from the bottom surface and the top surface of pavement base, when the semi-rigid base begins to crack. As the width of crack increases, the amplitude of negative reflected wave enlarges, and as the cracking in semi-rigid base is growing upwards from the base bottom, the negative reflected wave also gradually comes close to the positive wave reflected from the interface between the base and the surface. Besides, the effect of semi-rigid base cracking detected by ground -coupled GPR is better than that by air-coupled GPR.