In 2009, AAI completed drilling and overcore stress measurements under contract to HDR at the Duke Energy (Duke) Keowee Dam Spillway located at the Oconee Nuclear Station near Seneca, South Carolina. The principal purpose of the program was to drill observation core holes and measure the 2D stress in the concrete ogee of the Gate 1 and Gate 4 spillway bays. Tasks completed included:
- Coring and three in-situ stress determinations on approximately 5-foot centers in each of the two holes drilled vertically from the Gate 1 and Gate 4 spillway bays. Core was logged, photographed, boxed, and placed in a designated storage location.
- Drilling of six NX wireline (NXWL) observation core holes: two angle core holes into the west endwall from a work deck in the Gate 1 spillway bay; two angled core holes drilled into the east endwall from a work deck in the Gate 4 spillway bay; and two vertical NXWL core holes, one through each of the abutments adjacent to spillway bays 1 and 4. Core was logged, photographed, boxed, and stored.
- Video logging of boreholes. Boreholes were logged using an OBI-40 optical televiewer which collected a 360° borehole wall image, borehole dip, tool azimuth, and tool internal temperature. The OBI-40 image azimuth may be influenced by the steel in the gates.
- Holes were grouted with tremie-placed cementitious grout.
- A comprehensive report was provided.