Laboratory-scale soil mixing of a contaminated site

Abstract

The interpretation of the results of full-scale testing of treated contaminated ground and the correlation of these results with those from laboratory treatability studies are complex because of site heterogeneities, both in terms of the soils and the contaminants. In addition, the high costs usually associated with full-scale testing make laboratoryscale model testing of site conditions an effective means of correlating laboratory and in situ results. This paper presents details of laboratory-scale modelling of an in situ soil-mixing treatment of a contaminated site, for which a laboratory treatability study and a full-scale pilot in situ treatment had been carried out. The objective was to develop a correlation between full-scale soil mixing, laboratory-scale soil mixing and the laboratory treatability study. The correlation is presented in terms of physical and chemical properties, namely unconfined compressive strength, leachability, leachate pH, durability, permeability, compressibility and microstructural analyses. The results showed that reduced-scale laboratory modelling of in situ soil mix treatment of contaminated soils should be an integral part of the treatability study. The modelling was successful in duplicating certain in situ conditions which were not possible with conventional treatability study procedures.