In situ Determination of Elastic Moduli of Pavement Systems by Spectral-Analysis-of-Surface-Waves Method (Theoretical Aspects)

摘要

The theoretical aspects of the Spectral-Analysis-of-Surface-Waves (SASW) method are presented herein. The SASW method is used to determine the shear wave velocity and elastic modulus profiles of pavement sections and soil sites. With this method, a transient vertical impulse is applied to the surface, and a group of surface waves with different frequencies are generated in the medium. These waves propagate along the surface with velocities that vary with frequency and the properties of the different layers comprising the medium. Propagation of the waves are monitored with two receivers a known distance apart at the surface. By analysis of the phase information of the cross power spectrum and by knowing the distance between receivers, phase velocity, shear wave velocity and moduli of each layer are determined. The report contains a comprehensive discussion of the theories used in the in situ testing technique and the in-house data reduction procedure.