The relationship between thermal conductivity and electrical resistivity of silty clay soil in the temperature range − 20 C to 10 C

Abstract

With increasing engineering projects carried out in cold regions, the analysis and evaluation of the thermal conductivity and electrical resistivity of frozen soil have become important considerations in engineering construction and theoretical research. Through experiments performed on silty clay, the effects of the initial water content and soil temperature on the thermal conductivity and electrical resistivity of silty clay soil were analyzed. Theoretical models were also formulated for the soil thermal conductivity and electrical resistivity. The results showed that the variations in the thermal conductivity and electrical resistivity can be discussed as three stages: the freezing prophase, freezing metaphase and freezing anaphase. The electrical resistivity increases rapidly in the temperature range − 2 °C to −6 °C. The thermal conductivity increases rapidly from −2 °C to −4 °C and then decreases slightly from −4 °C to −6 °C due to the development of frost heave cracks in samples with higher water contents (15%, 18% and 20%). However, the thermal conductivity of samples with a water content of 10% continues to increase under these conditions. At the same temperature, the thermal conductivity increases linearly with water content in general. The electrical resistivity decreases approximate linearly with water content from 10 °C to −4 °C and increases with increasing water content from −4 °C to −20 °C. The thermal conductivity is inversely proportional to electrical resistivity from 10 °C to −4 °C and is proportional to electrical resistivity from −10 °C to −20 °C. The results of the experiments performed on silty clay soil verify the soundness of the proposed model for the thermal conductivity and electrical resistivity of unfrozen and frozen soil.