Abstract: Frozen soil is a special soil which is different from other general soils. Due to the limitations of the experimental equipment, means and other aspects, current research on the frozen soil is mostly limited to the macro perspective, but the analysis of the content and distribution of the unfrozen water in the frozen soil from the micro perspective is rarely conducted by combining nuclear magnetic resonance technology. In other words, the nuclear magnetic resonance technology is used to test the soil with the constant temperature and the different initial water content as well as the different temperature during freeze-thawing process, and the T2 curve is combined to analyze the occurrence of pores of the unfrozen water from a microscopic perspective. The freezing process includes three stages, namely, the subcooling stage, the rapid decline stage and the stable stage. The influence of the initial water content on the unfrozen water content at the same temperature of the same soil quality in the freeze-thaw cycle is analyzed, and the influence of the initial water content unchanged and the temperature on the unfrozen water content is also analyzed. Then the distribution of the unfrozen water is analyzed according to the change of the content of the unfrozen water, which provides ideas and methods for the later research combining the nuclear magnetic resonance technology with the frozen soils.

Key words: Frozen Soil, Nuclear Magnetic Resonance, Unfrozen Water Content, Pore Occurrence