PREDICTION OF INFLUENCE RADIUS OF VACUUM PUMPING IN UNSATURATED SOIL AND EVALUATION OF AIR PERMEABILITY BY IN SITU VACUUM TEST

Abstract

The coefficient of air permeability and the influence radius are the important indices for the design of remediation of the polluted unsaturated soil. At present, several theoretical formulas have been proposed to estimate the air permeability. However, neither theoretical formulas for estimating air permeability nor the influence radius of vacuum test affected by the volumetric water content are clarified.
In the present paper, the solutions by theoretical formulas were compared with numerical solution by the finite element method which considers the compressibility of air and the spatial distribution of volumetric water content. It was revealed that the theoretical formulas were applicable to the actual unsaturated soil where the in situ vacuum test was conducted.