SOIL CLEAN UP BY INSITU AERATION .4. ANISOTROPIC PERMEABILITIES

A method for determining the ratio of the vertical and horizontal permeabilities of soils to air is described. The method requires measurement of the gas flow rate in a vacuum well and the soil gas pressure at a suitably chosen point in the vicinity of the well. Soil gas pressures in the vicinity of a vaccum well in an anisotropic medium are calculated theoretically by using the method of images to construct a solution to Laplace's equation which satisfies the appropriate boundary conditions. Effects of well depth, depth of water table, and anisotropy are examined. A relaxation method is presented for determining soil gas pressure distributions when the permeability is both anisotropic and a function of position. It is shown that piezometer measurements in the vicinity of a vacuum well permit the location of strata of differing permeabilities. © 1990, Taylor & Francis Group, LLC. All rights reserved.