Soil Mixing: 8,900 CY (6,810 CM) of soil up to 25 feet (7.6 m) deep
Description of Work:
The purpose of this project was to use single auger soil mixing to treat TCE impacted soils in-situ. Geo-Solutions was subcontracted by CH2M Hill to be the prime contractor for this phase of the remediation. Geo-Solutions completed all portions of the work relating to soil mixing and subcontracted some of the general site preparation and earthwork items. The soil mixing required the installation of two hundred and twenty four 9 foot (2.74 m) diameter soil mixed columns to depths of 18 to 25 feet (5.5 m – 7.6 m) below workpad elevation. Each column was mixed with zero valent iron (ZVI) and bentonite slurry. The ZVI is meant to aid in reducing the TCE to less harmful constituents and the bentonite slurry reduces the permeability of the area thereby reducing flow through the contaminated zone and increasing the residence of time of contaminated groundwater that does flow through the contaminated zone.
All of the soil mixing work was completed using Geo-Solutions’ Delmag RH-18 drill rig, batch plant, and silos.
The mix area post mixing was almost completely inaccessible for equipment. The material was allowed to consolidate over a few months before the final geotextile cap was placed.