Keller's ground improvement program was completed 1.5 weeks ahead of the contracted schedule.
The project
A 16,000-square-foot aeration basin and two 5,000-square-foot clarifiers were to be constructed within an approximately five-acre site. Near-surface alluvial soils consisted of lean clay, silty clay, and clayey sand.
The challenge
The anticipated structural loading ranging from 1,600 to 3,500 lbs per square foot would have caused significant compression of the upper strata, resulting in an intolerable differential settlement between facilities. Removal and replacement of the upper 12 to 15 feet of site material would have required approximately 14,000 cubic yards of imported fill.
The solution
In lieu of removal and replacement of compressible soils, Keller designed and installed a ground improvement program consisting of over 1,000 vibro piers that would keep differential settlement to less than 0.75 inches. This program improved the allowable bearing pressures of the in-situ soils by increasing bearing capacity and reducing anticipated settlements to tolerable values.