Methodical features of field and laboratory dielectric permittivity measuring techniques for sand-clay ground

Information about the dielectric permittivity of deposits can be useful in the interpretation of GPR data, particularly in the context of sandy-clay ground. Among the methods for measuring electromagnetic parameters, greater preference is given to the Time Domain Reflectometry (TDR) method due to its ability to perform in situ measurements while preserving the natural density and moisture content of the deposits. However, its application requires open ground, such as a trench or a quarry wall, which are rarely found at the sites of geological and geophysical work. Much more frequently, various specialists drill wells and collect samples. In such cases, instead of the TDR method for measuring dielectric permittivity, a laboratory method using a coaxial cell is employed. The substitution of one method for another leads to discrepancies in the measured values, primarily due to changes in the sample's condition 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.

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