2020 Volume 72 Issue 6 Pages 397-400
Subsurface cavities potentially cause a catastrophic consequence, such as road cave-in. As a countermeasure, groundpenetrating radar method has been used to find subsurface cavities in shallow ground, whereas no established method is available to detect a cavity in deep ground. To understand micromechanics of wave propagation around a cavity, discrete element method (DEM) simulations were performed. The DEM analyses revealed that P-waves propagate faster along soil arching, whereas S-wave velocity is less sensitive to soil arching. Overall, both P- and S-wave velocities decreased due to loosening of soil where number of contacts per particle dropped in the vicinity of the cavity.