| Spectral analysis of surface wave (SASW) systems are an increasingly popular tool for the estimation of shear wave velocity profiles of geotechnical sites as a reasonable alternative to expensive and difficult downhole and crosshole tests. However, there are relatively few commercial systems using this new approach. The prime-objective of this study is to understand the application of a commercial SASW system manufactured by Olson Instruments, Inc. and to compare the results obtained with it to a Multi-Channel Analysis of Surface Wave system developed at the University of Rhode Island. For the field testing program, different sized sledgehammers and weights were used to impact the soil while measuring the passing Rayleigh surface waves with pairs of 4.5 Hz and 2 Hz geophones that were connected to a dynamic signal analyzer for different spacings. This data was processed in the programs WinTFS and WinSASW to develop site-specific dispersion curves, which were then inverted to estimate shear wave velocity profiles. After preliminary testing, the system was used to conduct tests at different sites where investigations of shear wave velocity with different systems have already been performed. Additionally, tests were performed at two different beach sites to collect data that might be useful to explore the relationship between soil stiffness and coastal erosion. The results showed some agreement from inversions using a different system and software package. Nevertheless, there is still a need for further investigation to examine the reliability of the measurements and analysis methods. |
