Application of advanced borehole geophysics in site geological, geotechnical and environmental characterization

Geological and environmental subsurface characterization programs usually consist of simple, uncalibrated borehole geophysical logging suites consisting of natural gamma and resistivity tools. Although basic lithologic and hydrogeologic data may be interpreted from these curves, it is difficult to determine the geologic conditions that control contaminant flow and transport or to evaluate basic rock properties such as density and porosity, that may impact geotechnical considerations. Advanced logging tools, such as magnetic resonance, digital sonic and spectral gamma, may be correlated to standard tools such as CPT and ground penetrating radar data. Correlating advanced geophysical data to standard tests in recent programs has demonstrated that 1) stratigraphic intervals with variable geohydrologic and geotechnical properties may be defined, 2) sediment properties, such as Poisson's Ratio, may be directly measured and related to specific geological members, and 3) the direct association of certain contaminants to a specific stratigraphic interval, may be possible.