Soil Mixing: 7,626 CY (5,834 CM) of soil up to 19 feet (5.8 m) deep; 95% Self-Performed
Description of Work:
The purpose of this project was to use single auger soil mixing to treat TCE contaminated soils using a two-step approach: 1) In-Situ oxidation with Potassium Permanganate (PP) and 2) In-Situ solidification with Portland cement (PC). Geo-Solutions was contracted to complete all of the soil mixing work as well as other site preparation / clean-up activities. These site preparation / cleanup activities included excavation and stockpiling of approximately 1,500 CY (1148 CM) of clean overburden, installation of 14 trench bedding “plugs” to minimize PP migration off site, erosion and sediment control installation, monitoring well installation, utility abandonment, and site landscaping. Some of these activities were subcontracted, but Geo-Solutions self-performed the majority of the work. The soil mixing required the installation of two hundred and forty two 9 feet (2.75 m) diameter soil mixed columns to depths of 17 to 19 feet (5.2 m – 5.8 m) below workpad elevation.
All of the soil mixing work was completed using Geo-Solutions’ Delmag RH-18 drill rig, batch plant, and silos. In the course of the soil mixing work, Geo-Solutions encountered over fifty 14-inch (356 mm) diameter deep foundation concrete piles. The construction team decided that the best approach to dealing with these piles was to “isolate” the obstructed columns, excavate the obstructions to the maximum possible depth, and treat the previously obstructed columns. This approach worked as planned and was executed without a great deal of delay to the original schedule.