Augered Pile World Record Depth Within a Soil Mix Basement-Paper

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The Estates at Acqualina in Sunny Isles Beach, Florida, comprises two 50-story towers with a two-level underground parking garage. Its beachfront location, highly permeable limestone, and groundwater only a few feet below grade made basement construction especially challenging.<br /><br />A design-build joint venture between HJ Foundation and Hayward Baker created a “dry hole” using deep soil mixing. Cement slurry was mixed with the existing ground to form an impermeable soilcrete bottom seal covering about 130,000 square feet. A 2,300-foot soil-mix secant pile wall enclosed the excavation, with additional tieback anchors along part of the north wall. The system enabled excavation to 34 feet below grade—about 30 feet below the water table.<br /><br />Approximately 1,000 auger-cast piles were installed to support the towers, garage, and podium. Tower piles were designed to carry up to 1,290 tons after load testing. One reinforced production pile reached 182.3 feet (55.6 meters), establishing a record for the deepest single-pass augered pile at the time. The piles also helped resist uplift on the soil-mix seal. Vibrated aggregate columns were used in the entrance area to improve the ground without conflicting with planned utilities.<br /><br />The project team completed the South Tower excavation and foundation work within an aggressive 26-week schedule. More than 100,000 cubic yards of material were excavated, and measured water intrusion after completion was less than 100 gallons per minute.<br /><br />Quality assurance included continuous monitoring of soil-mixing and pile-installation data, field sampling, laboratory testing, and static load tests. Daily safety briefings and defined work zones helped coordinate simultaneous heavy-equipment operations. The project demonstrates how deep soil mixing, combined with deep foundations, can make below-grade construction feasible in difficult, high-groundwater conditions.

Keywords

Estates at Acqualina

Sunny Isles Beach

deep soil mixing

soilcrete

basement construction

groundwater

auger-cast piles

secant pile wall

load testing

foundation engineering