To reduce groundwater seepage from the base of the excavation, jet grouting was employed to create a seal slab. This process involves the injection of high-pressure grout into the ground through a drill string as it is rotated, creating a solid and impermeable column of treated soil. A bottom plug was created by constructing numerous overlapping columns of treated soil at the base of the excavation to cutoff water. A significant quantity of jet grouting was performed on the project, with over 6,200 cubic yards of soil being treated. This extensive application of jet grouting ensured a strong and reliable plug for the cutoff wall, effectively reducing the groundwater seepage and enhancing the overall stability and integrity of the excavation.

Tiedown anchors were installed at the base of the excavation to ensure stability and prevent potential issues such as heaving. The project included over 9,000 linear feet of tiedown anchors installed to depths of 80 feet. The tiedown anchors were installed with a crane with hanging leads with a continuous flight auger. The anchors were drilled through the jet grout plug after it was completed and reinforcing bars were used to create tensile capacity for the tiedowns.