Finite element GPR numerical simulations based on mixed boundary conditions

With the consideration of different theoretical mechanisms for the transmitting and Sarma boundary conditions, a mixed boundary condition is proposed that combines both boundary conditions. This enables the remaining energy of a GPR wave to be transmitted through the boundary after it is attenuated and absorbed as specified by the Sarma boundary condition, thereby integrating the advantages of the two conditions. The processing effects on GPR waves that reach the truncated boundary using the mixed boundary condition are superior to the processing using a single boundary condition. Finally, numerical simulations of a typical electrical property model of the earth is carried out using a finite element method based on the mixed boundary condition, and recommendations for effective GPR data processing and engineering practice are presented.