Use of the Cone Penetrometer in Geotechnical and Environmental Testing

A simple cone penetrometer was first used in the late 1930s by the Dutch to check ground water levels in Holland. Development of a much more sophisticated cone penetrometer for modern environmental site characterization has been an on-going development program at Argonne over the past decade. Supported by the USDA, the current effort is focused on characterizing grain bin sites where fumigants were used in the 1950’s and 60’s. Unfortunately, the fumigants contained carbon tetrachloride and other chemicals that are now known to be carcinogens. These contaminants often entered the soil, and in some cases, have also entered groundwater and major aquifers. The USDA is focused on locating and characterizing these sites, and employ appropriate remediation steps where possible.

Argonne uses cone penetrometer technology as a primary means of data acquisition during site characterization. It is efficient, minimally invasive, and cost effective. The modern electronic cone is capable of measuring, among other things, the penetration rate, tip resistance, sleeve friction, and conductivity of the soil. The electronic cone is forced into the ground using from ~20 to 40 tons of force exerted through large but portable hydraulic systems. Core and water samples in a vertical sequence can also be taken for chemical analyses, and piezometers can be installed at different depths to monitor ground-water levels subsequently used to determine the primary direction of groundwater flow in an aquifer system. With this information, both stratigraphic/structural and hydrostratigraphic cross-sections can be constructed and the extent and preferred migration pathways of contaminants can be determined.

For analyses of specific subsurface contaminants, the cone penetrometer can be instrumented with x-ray florescence (e.g., for detection of heavy metals); with gamma-ray spectroscopy (for radionuclides); as well as optical and electrochemical sensors (for chlorinated organics and explosives). The development of new instrumentation for additional data acquisition and rapid on-site analysis is a key part of the Argonne work.

As more contaminated sites are characterized, Argonne is working with the USDA to help select and (in some cases) implement appropriate remediation technologies, including phytoremediation and other bioremediation techniques, barrier walls, pump and treat technologies, etc. On August 18-20, 2004, Argonne offered a course on Cone Penetration Testing to help transfer the latest technology to private industry as well as to share it with other environmental research organizations.