Thermal Conductivity and Freezing Temperature of Oil-Contaminated Foundation Soils Surrounding the China-Russia Crude Oil Pipeline

摘要

Thermal properties of soils surrounding an oil pipeline might vary greatly after being contaminated by oil. This study investigates this variation and its mechanisms by laboratory measurement of the thermal conductivity and freezing temperature of typical oil-contaminated foundation soils surrounding the China-Russia Crude Oil Pipeline (CRCOP). The results show that the thermal conductivity of the contaminated soils increases with increasing water content when the dry density remains constant. The conductivity initially decreases and then sharply increases, finally decreasing again with increasing oil content. The influence of temperature on thermal conductivity depends mainly on whether the pore water is frozen or unfrozen. The thermal conductivity is jointly controlled by location (absorbed around soil particles or freely existing in pore space), phase state (liquid or solid state), amount of liquid phase in soil (water and oil), and soil type. The freezing temperature of the contaminated soil decreases with increasing oil content. The varying mechanisms of the thermal conductivity and freezing temperature are described in detail. Results are important and valuable for the evaluation and forecast of oil migration, for environmental protection, for permafrost degradation, and for engineering stability.