APPLICATION OF THE ELECTRICAL IMPEDANCE SPECTROMETRY FOR MONITORING WATER FLOW IN UNSATURATED SOIL

Abstract

Aim of paper The aim of research was to determine the sensitivity of the impedance spectrometry method (EIS) to changes in electrical resistance of soil caused by water infiltration. Materials and methods Two types of mineral soil were considered in the research: fine sand and coarse silty sand. The research was to determine basic geotechnical properties of both soils (filtration coefficient, soil-water characteristic curve) and water infiltration tests in a vertical soil column. These tests included measuring changes in electrical resistance of soil medium, which were compared with observations of the location of the wetting front and numerical calculations of water flow through the soil. Infiltration tests were run for three soil samples. The first was a sample of medium sand, the second coarse silty sand, and the third medium sand in the lower part and coarse silty sand in the upper part. Results and conclusions The results of tests of electrical resistance of soils subjected to infiltration process in vertical column confirmed the significant impact of water in soil medium on its electrical conductivity. It has been shown that a change in soil moisture from an air-dry state to full saturation leads to a reduction of soil resistance by almost three orders of magnitude.