During the summer of Fiscal Year 1997, a Comprehensive Environmental Response, Compensation, and Liability Act Treatability Study was performed at the Idaho National Engineering and Environmental Laboratory. The study involved subsurface stabilization of a mixed waste contaminated soil site called the Acid Pit using jet grouting of an innovative grouting material to form a monolith out of the contamination zone. The monolith simultaneously provides a barrier to further contaminant migration and closes voids in the soil structure against fi.uther subsidence. The grout used for this study was TECT-HG, a relatively dense iron oxide-based cementitious grout. The treatability study involved both cold testing in simulated soil pits followed by in situ stabilization of the Acid Pit at the INEEL's Waste Area Group 7 Subsurface Disposal Area. This report (volume 1) discusses the results of the cold testing phase of this project, and Volume 2 gives the results of the Acid Pit stabilization. Cold testing included field trials in which single and multiple connected columns were created by the jet-grouting action. In addition, several different simulated soil pits were grouted using tracer material to simulate actual contaminants that exist in the Acid Pit. Drilling equipment was specially rigged to reduce the spread of contamination, and all grouting was performed under a concrete thrust block with void space to absorb any grout returns. Data included evaluation of the grouting parameters of drill rotation rate, time at a step, grout injection pressure, grout material parameters such as vismsity, and step size. In addition, the spread of the tracer material (molybdenum powder) as a stand-in for the actual main contaminant (mercury) in the Acid Pit during grouting was evaluated by taking both air samples and surface smears. Other implementability data included thrust block reusability, grout column development and connectivenem, and grout/soil mixing.

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