For evaluating subsurface contamination, sampling method (boring) is commonly used, but this method cannot monitor the change of in-situ contamination and concentration with respect to time. The purpose of this study is to develop a measuring system for subsurface contamination in which a so-called FDR (Frequency Domain Refiectometry) and FDR-V (with Vector network analyzer) system was employed to measure the salinity and oil contaminant. This FDR and FDR-V method is a coaxial probe method, which allows the measurement of the dielectric. The experimental study indicates the possibility in measuring both the contaminant concentration and volumetric moisture content. In addition, the method for obtaining the effective porosity using this equipment was shown. Concretely, the sensor was inserted in the ground, and the liquid in which the dielectric constant differed on the water in the circumference was injected, and the method for obtaining the effective porosity from the change of the dielectric constant was proposed.
Frequency Domain Refiectometry