Abstract: In view of the electrical characteristics of the media of different potential geological defects in embankment, corresponding geophysical models are built using the finite difference time domain (FDTD) algorithm with the perfectly matched layer absorbing boundary conditions (PML). GprMax software together with MatLab self-programming is employed for the GPR forward simulation. Result reveals that the amplitude and form of GPR reflected wave of hidden defects vary with shape, location, and electrical parameters. Forward simulation result accurately reflects the depth and horizontal position of hidden defects. Two engineering examples demonstrate that the results of GPR forward simulation are basically consistent with engineering verification, which proves that GPR can effectively detect the hidden dangers of embankment. The GPR forward simulation method is feasible, and is helpful to guide the further interpretation work more precisely.

Key words: detection of hidden dangers in embankments, ground penetrating radar (GPR), hidden defective body, finite difference time domain(FDTD) algorithm, geophysical model, wave field characteristics, forward modeling