Imaging the Stratigraphy Around a CPT Penetration Using a Combined ERT and CPT Method

In order to determine the fate and transport of contaminants generated from past weapons production activities, there is a need to measure the key factors that affect the flow and transport of water and contaminants in the shallow subsurface. Specifically, a method is needed for the real-time imaging of the stratigraphy in the shallow subsurface within 40 meters or more of a CPT (cone penetrometer technology) push or a monitoring well as the penetration is conducted. This project will develop a method to accomplish this imaging, using electrical resistance measurements between an array of electrodes along the groundsurface and a electrode mounted on the CPT probe. Phase I will use numerical modeling and scaled laboratory tests to evaluate the feasibility of using electrical resistance tomography (ERT), implemented with CPT, to image the subsurface stratigraphy within several meters of the CPT location. Commercial Applications and Other Benefits as described by the Applicant: Current subsurface characterization techniques typically provide only point measurements and are not able to reach out past the borehole location to determine whether layers are continuous or pinch out away from the borehole. The combined ERT-CPT approach should permit real-time mapping of the subsurface stratigraphy several meters away from the borehole, providing a much improved image of the subsurface.