Sparrow's Point, MD: In-Situ Soil Mixing, Gray's Landfill Ground Improvement
In order to facilitate the additional loading of an existing landfill, Geo-Con was contracted to install a series of soil-mix columns at the base of the landfill to address the potential failure of the underlying soils. The soil mix columns extended through a soft clay layer, adding the shear strength necessary to safely increase the height of the landfill without the possibility of slope failure.
One hundred and twenty, ten-foot diameter, soil-mix columns were installed to a depth of thirty feet below ground surface (bgs). Soil mixing was accomplished using Geo-Con's custom-built Calweld drill turntable mounted on a Manitowoc 4100 crane. Cement Grout, produced in Geo-Con's batch plant, was pumped through the hollow-stem Kelly Bar and injected through ports on the ten-foot diameter mixing auger.
Geo-Con met and exceeded the extremely stringent quality control/quality assurance specifications set for the project. Shear strength and column soil-mix homogeneity was confirmed through the combination of column coring and in-place pressure-meter testing. Geo-Con met the required ninety-day shear strength of 18,200 pounds per square foot (psf) typically in less than 14-days allowing the client to accelerate the schedule for the completion of additional phases of the project. The project was completed ahead of schedule and with zero health and safety related incidents.