The Methodological Features of Field and Laboratory Dielectric Permittivity Measuring Techniques for Sandy-Clay Deposits

Information about the dielectric permittivity of deposits can be useful in the interpretation of GPR data, particularly when studying a sandy-clay sequence. Among the methods for measuring electromagnetic parameters, greater preference is given to time domain reflectometry (TDR) due to its ability to perform in situ measurements while preserving the natural density and moisture content of deposits. However, its application requires open ground, such as an open pit or a quarry wall, which are rarely found at the sites of geological and geophysical surveys. Much more frequently, core samples are collected. In such cases, instead of the TDR method for measuring dielectric permittivity, a laboratory coaxial cell method is applied. The substitution of one method for another leads to discrepancies in the measured values, primarily due to changes in the condition of the sample compared to the natural state of the soil. Therefore, this study analyzes the magnitude of these discrepancies in artificial and natural sandy-clay deposits depending on the grain size distribution and moisture content.