Numerical Simulation and Experiment for the Bottom Boundary of Riprap of Seawall by GPR

Seawall engineering is essential in preventing typhoon storm surge disasters in coastal areas. Usually, the engineering measure of throwing the stone to form a riprap layer is adopted to enhance seawall stability and anti-erosion property. Determining the thickness of the riprap layer is an essential step in the evaluation of engineering measurement, and the key is to determine the burial depth of the bottom boundary of the riprap. A seawall is taken as the research object. The propagation process of the electromagnetic wave in the seawall is simulated by the finite difference time domain (FDTD) method, the propagation law and profile response characteristics of the electromagnetic wave are obtained, and the method's feasibility is confirmed theoretically. Further field test and drilling detection results are used to calibrate the electromagnetic wave velocity, and the top and bottom interface of the riprap layer is divided, which provides a basis for the measurement of the riprap body.