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Correct use of cone penetrometer sensors to predict subsurface conditions

Description: When cone penetrometer testing (CPT) technology is used with in-situ sensors and probes to characterize subsurface conditions in environmental investigations, each sensor must be calibrated with high quality, site specific data to establish essential interpretation criteria. Mechanical, geophysical, and chemical sensor data collected for a site in South Carolina without such controls were misleading. Core logs obtained subsequently had major lithologic discrepancies with the soil classification based on the CPT sensor data. In addition, detailed core sampling and laboratory analysis showed that the sensor data on chemical contaminants included false positive and false negative results. In contrast, for a site in Nebraska, CPT data calibrated with high quality site controls provided a detailed interpretation of subsurface conditions relevant to contaminant fate and transport. On the basis of the work in Nebraska, Argonne scientists are continuing to develop criteria to improve the interpretation of complex subsurface stratigraphy.
Date: September 1, 1997
Creator: Walker, J.L.; Rose, C.M.; Armstrong, S.C. & Burton, J.C.
Partner: UNT Libraries Government Documents Department

Collecting real-time soil moisture profiles in the vadose zone

Description: The savings realized by using cone penetrometer (CPT) technology to supplement site characterization work are well documented. Adding soil moisture profiling to CPT testing can further enhance the interpretation of geologic and hydrogeologic conditions at a site. The performance characteristics of three soil moisture probes (SMPs) used with direct push technology were tested at a site in South Carolina. In the unsaturated zone, all three probes predicted volumetric soil moisture within {+-}5 moisture units of the laboratory values more than 65% of the time. When the results were outside this range, the difference was not large enough to lead to erroneous interpretations of the actual soil moisture trends. Results of testing in a variety of hydrogeologic conditions indicate that when SMPs are used with proper site calibration and controls, each probe can predict soil moisture values within the unsaturated zone that closely match laboratory results, in real time.
Date: September 1997
Creator: Rose, C. M.; Armstrong, S. C.; Walker, J. L.; Young, G. N. & Burton, J. C.
Partner: UNT Libraries Government Documents Department