Acoustic landmine detection: a 3D poroelastic model

Acoustic waves can be a viable tool for the detection and identification of land mines, unexplored ordnance and other buried objects. Design of acoustic instruments and interpretation and processing of acoustic measurements call for accurate numerical models to simulate acoustic wave propagation in a heterogeneous soil with buried objects. Compared with the traditional seismic exploration, high attenuation is unfortunately ubiquitous for shallow surface acoustic measurements because of the loose soil and the fluid in its pore space. To adequately mode such acoustic attenuation. , we propose a comprehensive multidimensional finite-difference time-domain model to simulate the acoustic wave interactions with land miens and soils based on the Biot theory for photoelastic media. For the truncation of the computational domain, w use the perfectly matched layer (PML). The method is validated by comparison with analytical solutions. Unlike the pure elastic wave model, this efficient PML-FDTD model for photoelastic media incorporates the interactions of waves and the fluid-saturated pore space. Several typical and mine detection measurements are simulated to illustrate the application.