Air Permeability from Pneumatic Tests in Oxidized Till

Abstract

Soil vapor extraction (SVE) to remove volatile contaminants from contaminated soil in the unsaturated zone has been successful in sand and gravel formations. In less permeable glacial till, the usefulness of SVE is unclear. Field experiments in the loam till of central Iowa were performed to determine air permeabilities. A radial and vertical, anisotropic, heterogeneous compressible‐flow model coupled with an optimization routine solved the inverse problem by using vacuum pressure and flow‐rate data to estimate air permeabilities. Air‐permeability anisotropy was determined to be less important than depth variations. Using a four‐layer description of the deposit to account for varying moisture content with depth, the average predicted air permeability varied from