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Tennessee Valley Authority (TVA)

Owner/Client: Tennessee Valley Authority (TVA)
Location: Eastern Tennessee and Western North Carolina
Services: Drilling

Geotechnology, Inc.’s Drilling Division was asked to provide a variety of drilling services to URS Corporation in support of their evaluation of five existing concrete dams operated by the Tennessee Valley Authority (TVA). These dams, constructed in the 1940’s and 1950’s, were evaluated as part of a larger evaluation program in support of TVA’s permit application for an additional nuclear unit at its Watts Bar Plant.

All work was performed under TVA’s comprehensive safety and environmental protection program. The core holes along the crest of the dams were particularly challenging due to very limited space and on-going operations at the dam. Despite these challenges, Geotechnology’s crews completed all fieldwork without any interruptions to dam operations or violations of TVA’s strict environmental and safety policies.

Geotechnology, Inc. was initially assigned work at only the Boone Hydro Plant in Kingsport, TN. However, due to the crews’ productivity and commitment to quality and safety, Geotechnology, Inc. was ultimately awarded an entire second site (Melton Hill) and assisted other drilling contractors at Apalachia Dam and Ft. Patrick Henry Dam. Ultimately, Geotechnology, Inc. crews cored more than 2,700 lineal feet of in place concrete and underlying metamorphic bedrock with a core recovery greater than 99%. In multiple cases, our crews were able to recover the dam/bedrock contact as an intact core.

Services required included wireline core sampling of the dam structure and the underlying bedrock using a combination of PQ (3.25” core) and HQ (2.50” core) tool strings. Core holes were packer tested and electronically logged upon completion. Additionally, soil borings, rock core borings and piezometers were installed in the abutments of each dam.