Detection of Underground Obstacles by SASW Method—Numerical Aspects

Abstract

The ability of the spectral analysis of surface waves (SASW) test to detect underground obstacles has been investigated. The SASW test is simulated by the finite-element method. The fluctuations in the dispersion curve, due to Rayleigh waves reflected from an obstacle, are used to detect the obstacle. Both rigid obstacles and cavities with a variety of shapes and embedment depths are considered. Obstacles in a homogeneous half-space, a layered half-space, and a pavement profile are detected. Finite-element results are compared to the available experimental results and verified by a simple mathematical model. The results indicate that the SASW test can detect an underground obstacle effectively, provided that the obstacle is relatively close to the surface. A scheme to use the surface waves for obstacle detection (SWOD) has been proposed.