In situ determination of elastic moduli of pavement systems by spectral analysis of surface waves method (theoretical aspects)

Abstract

The Spectral-Analysis-of-Surface-Waves (SASW) method is an in situ testing method for determining shear wave velocity profiles of soil sites and stiffness profiles of pavement systems. The method is non-destructive, is performed from the ground surface, and generally requires no boreholes. The key elements in SASW testing are the generation and measurement of surface waves. Two receivers are located on the ground surface and a transient impact containing a large range of frequencies is transmitted to the soil by means of a simple hammer. One of the most important steps in SASW testing is the inversion process, an analytical technique for reconstructing the shear wave velocity profile. Data collection and analysis used in the SASW technique are discussed in detail. Several case studies are presented to illustrate the utility and versatility of the SASW method. In each case, the results are compared with those of other well-established testing methods performed independently at the same locations. Generally, the shear wave velocity and Young's moduli profiles from these independent methods compare closely.