A combination of equipment and techniques for the installation of the secant piles

Treviicos-Nicholson JV selected the secant piles for the construction of the cutoff wall part of the Boone Dam Internal ErosionProject.

The secant piles were installed using a combination of equipment and techniques: piling rigs were used to drill through the embankment and the alluvial, to depth of approximately 100 ft, using segmental casings. Reverse circulation top pile rigs then completed every pile, to a total maximum depth of circa 170 feet, into a rock with peak UCS values as high as 36,000 psi (240 MPa). 

The concrete for the piles was manufactured in an onsite batch plant operated and controlled by joint venture. 

The quality of the joints between the elements was of paramount importance for the integrity of the wall. An extensive quality control program provided TVA with an accurate validation of the installed final product for an early acceptance both during the project and for final approval. This, in conjunction with an equally extensive quality assurance program, ensured that the cutoff wall was installed meeting or exceeding the stringent requirements of the Project.