Effect of Stress on the Effective Dielectric Permittivity of a Silty Clay Soil

Geophysical approaches are nowadays widely used in many fields of geotechnical engineering and energy geotechnics in monitoring the temporal and spatial variations of moisture content and other soil parameters. As majority of these engineering projects are founded at underground levels of soil deposits which are subjected to significant overburden pressures from the soil itself and loads from the superstructure, understanding the influence of applied stress on the dielectric behavior of soils is of high significance. On this basis, the results of theoretical and experimental investigations of the effect of stress on the effective dielectric permittivity of an unsaturated silty clay soil from Germany performed using a non-destructive high frequency electromagnetic (HF-EM) technique are presented in this study. The findings show a significant dependence of the effective dielectric permittivity of the silty clay soil with effective stress, and a satisfactory match between the theoretical model prediction and the observed experimental data.