Determination of Homogeneity and Isotropy of Soil Using Geophysical Methods.

Abstract: Cognition of the hydraulic properties of soils is important in civil and environmental projects such as for water supply, geotechnical investigations and evaluation of pollutant spreading. This pilot project aims to develop and test a new method for characterization of the homogeneity and isotropy of different soils by using geophysical measurements. The method is based on geoelectrical (resistivity) measurements using a radial array. Using a radial array with electrode lines in various orientations crossing a midpoint at which water was infiltrated, it was possible to build a 3D-block model showing the water penetration into a soil body. Based on the infiltration pattern it was possible to evaluate the hydraulic heterogeneity and anisotropy of the material. Several common Swedish types of soils were tested. Measurement and evaluation techniques including software were developed. The project shows that geoelectrical measurements using a radial array and geoelectrical instruments available on the market can be used for rapid evaluation of the hydraulic heterogeneity and anisotropy of soils and rock.