A novel freezing point determination method for oil-contaminated soils based on electrical resistance measurement and its influencing factors.

The traditional testing methods for freezing point measurement cannot accurately and quickly determine the freezing points of soils with a low water content and/or oil. Therefore, a new measurement method, which is more precise and has less error or deviation, was developed to determine the freezing point of soil and was verified by a series of laboratory tests. Additionally, the effects of oil content, water content, soil type, and dry density on freezing point were investigated. The results show that the water/oil mixing sequence remarkably affects the freezing point of sandy organic silt and lean clay; however, it does not affect the freezing point of poorly graded sand with silty clay. At water contents of <15%, the water content affects the freezing point more than the oil content does. At a water content of 5%, the freezing point decreases with increasing oil content. The effect of oil content on freezing point gradually decreases with increasing water content. At the same water and oil contents, the freezing point decreases with decreasing grain size. Moreover, the dry density has little effect on freezing point. The experimental results reveal the factors affecting the freezing point and their influencing mechanism, and provide important thermal parameters for thermal calculation for cold regions engineering.