Advanced Continuous Surface Wave Testing (ACSW): Geologic and Geotechnical Site Characterization for the 21st Century-Video

Video Transcription

Video Summary

The presentation introduces advanced continuous surface wave (ACSW) testing, a rapid, non-intrusive geophysical method for measuring subsurface stiffness. A vibrating shaker generates Rayleigh waves, which are recorded by six geophones across a short array. By controlling wave frequencies, the system estimates stiffness at different depths and converts the measurements into shear-wave velocity and elastic moduli. The speaker argues that ACSW can complement boreholes and conventional tests by providing bulk ground-stiffness profiles quickly and at relatively low cost—typically 12–20 tests per day—without drilling, utility conflicts, or contaminated spoil.<br /><br />The resulting small-strain stiffness data can be adjusted for expected strain levels and used in foundation design, ground-improvement verification, and site characterization. Examples include testing through concrete, investigations after the Surfside condominium collapse, landfill profiling, and quality control for rapid impact compaction. The technique has limited depth compared with deeper seismic methods, but its live data checks help ensure reliable measurements.

Keywords

continuous surface wave testing

subsurface stiffness

Rayleigh waves

shear-wave velocity

geophysical site characterization