This project involved Pressure Grouting with a Cement / Flyash grout material. The foundation construction of a new cooling tower for a Nuclear Power Plant posed many unique foundation challenges.
Three Sheet Pile Cofferdams were installed to permit excavations up to twenty feet below grade. Two Cofferdams used Tremie Seals to prevent the inflow of water from the bottom. In order to seal the interlocks of the sheet piling to prevent groundwater leakage, and increase the skin friction of the piling to reduce uplift potential, grouting was used.
A Grout Plug was installed on the third cofferdam in lieu of a tremie seal. This Cofferdam, unlike the others, had reasonably sound bedrock at the bottom of the proposed excavation. Steel Casing was installed through the overburden and the rock was drilled to design depth.
Packers were set to isolate the location of the Grout Plug beneath the proposed excavation. Grout was injected into the limerock to fill voids and water courses. Secondary grout holes were installed in areas with larger than normal grout takes. The Grout Plug proved to be a cost effective alternative to a conventional Tremie Seal.
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