Study on the Effect of Temperature and Water Content on Conductivity of Soil in Tibet of China

In recent years, with the continuous increase of electricity demand, power grid engineering in China has been built on a large scale. The soil conductivity is very important to the construction of power system. In this paper, on-site excavation and soil collection was carried out in Tibet of China. And soil samples near and away from the river were collected. The basic parameters such as soil texture, soil resistivity, soil water content, soil pH, soil chloride ion content, redox potential, soil salt content, self-corrosion potential and self-corrosion current density were tested in the laboratory. The soil characteristics in Tibet of China were obtained, then the effect of temperature and water content on soil resistivity was studied. The results show that soil resistivity is inversely proportional to temperature under different water content. The lower the water content is, the greater the effect of temperature on soil resistivity is. When the temperature is below 0 °C, the resistivity decreases rapidly with the increase of temperature. When the temperature is above 0 °C, the resistivity decreases slowly with the increase of temperature. In the environment of low water content (5%-20%) below 0 °C, the resistivity decreases rapidly with the increase of water content. When the water content is more than 20%, the content of water in the soil is large. The water and the soil are obviously stratified. And the low temperature leads to the freezing of the soil, so the resistivity is on the high side as a whole. When the temperature is above 0 °C, the soil resistivity decreases rapidly with the increase of water content. And when the saturated water content is exceeded, the soil resistivity increases slowly with the increase of water content. The resistivity below 0°C is much higher than that above 0°C. The research results could provide reference for the design, safe operation and maintenance of the power systemin Tibet of China.