Use of Geophysical Methods in a Geotechnical Investigation

This paper describes a case study in which a geotechnical investigation encountered complex subsurface conditions requiring geophysical methods to supplement test boring data. Electromagnetic (EM) and seismic refraction methods were used to model subsurface conditions at the site of a proposed three-story office building. The three investigative techniques used in this study all revealed bedrock to be at a shallow depth. The test borings provided vertical resolution while the EM and seismic studies yielded lateral resolution. Good correlation was achieved when comparing the results of each method. The EM and seismic methods in conjunction with a test boring program can provide a better understanding of subsurface conditions than can be obtained by any single technique.