Keller companies HJ Foundation and Hayward Baker have developed a solution that enables the construction of larger, deeper basements in areas with a high underground water table.
Using Hayward Baker’s soil mixing with HJ Foundation’s augercast piling, the technique involves injecting cement slurry into the ground through a tool that simultaneously mixes it with the in-situ soil, creating a soilcrete material that’s strong and almost impermeable, anchored down with CFA/augercast piles.
When applied to the perimeter and below the planned basement, the excavation can be performed with minimal seepage from the sides and below.
In South Florida, the water table is less than a metre below the surface and the soil and rock are highly permeable, so construction of basements can be challenging according to Keller.
HJ Foundation project manager Nick Feldt said: “Historically, when building basements in south Florida, contractors had to continuously pump tremendous amounts of water in the shallow groundwater, porous rock conditions.
“The difficulty is, as you go deeper, the pressure of the water increases and you get to a certain point where you no longer have enough power to pump all the water out, or a place to dispose of it.
“Because of environmental regulations, the water you’re pumping out has to be contained and reinjected on site and reinjection wells can only take so much. So, for developers in this area they’re really limited in how far underground they could go.”
For the past six years this joint venture between HJ Foundation and Hayward Baker have refined the solution that allows much larger basements, over 1180m² and up to three storeys underground, with deeper basements currently being proposed.
The solution combines Hayward Baker’s soil mixing with HJ Foundation’s augercast piling.