Test Results Of Cpt-Deployed Vertical Electrode Arrays At The Doe Hanford Site

Field studies were conducted at the DOE Hanford Site to test cone penetrometer installation of<br>vertical electrode arrays (VEA) for use with Electrical Resistivity Tomography (ERT). Most<br>VEA installation methods in current use are not economic for environmental applications. The<br>cone penetrometer technology (CPT) can provide an economic and relatively non-intrusive<br>installation method. However, a VEA with deployable and properly functioning electrodes was<br>required. Results of the design, installation and testing of CPT VEAs are reported in this paper.<br>Several designs were developed and bench tested for use with the CPT. After initial field<br>installation studies, one design was chosen for further testing at the DOE Hanford Site. Four<br>VEAs were each pushed to 100 feet in 4 days. To test the CPT VEAs, an infiltration experiment<br>was conducted with cross VEA tomographic data collected for three vertical planes. These data<br>were processed using the electrical resistivity tomography code developed by Lawrence<br>I,ivermore National Laboratory (LLNL). Tomographic images for each vertical plane tracked<br>the subsurface resistivity changes associated with the migrating fluid.<br>It is concluded from these test results that the CPT is a viable method for installing VEAs. The<br>VEAs were rapidly and economically installed to the maximum depth required, data of adequate<br>quality were obtained and tomographic images from the infiltration experiment verified that the<br>CPT VEAs provide viable ERT data.