Thermal effects on the electrical characteristics of Malan loess

Malan loess is a common engineering geological material in Northwest China, which is often used in many engineering constructions. In this paper, the electrical properties of loess under high temperature environment are studied, which provides theoretical basis for engineering construction. The remolded loess samples are heated by different temperatures between 25 and 900 °C under laboratory conditions. Then, the surface features and electrical properties are measured and analyzed. The major findings are as follows: (1) The effect of high temperature on different electrical parameters of loess is different. As temperature increases, a series of physicochemical reactions occur in the loess; as a result, the resistance and impedance of loess samples initially increase and then decrease. The temperature of change trend changes between 500 and 600 °C, which fits the normal distribution. The capacitance of loess decreases first and then slowly increases with increased temperature. The temperature of change trend changes between 200 and 300 °C. (2) The experimental results also show that frequency has an important effect on the measurement of electrical parameters. As the frequency increases, the resistance, capacitance, and impedance decrease. In addition, at high frequencies, the electrical properties of loess are basically not affected by temperature. Therefore, using a frequency of 100 Hz is more advantageous to study the variation law of the electrical properties of loess.