Pore Structure and Fractal Characteristics of Frozen-Thawed Soft Soil

Freezing action always results in great damage to the pore structure and fractal characteristics of freezing-thawing soft soil. Nuclear magnetic resonance (NMR) can help collect data to describe the microstructure of frozen-thawed soft soil. This paper conducted a series of nuclear magnetic resonance (NMR) tests to interpret the effect of freezing duration, freezing-thawing pressure and freezing temperature on soil's micro-pore structure and fractal characteristics. The pore size distributions (PSDs) of the tested materials were obtained from the NMR T-2 spectra, and fractal theory was introduced to describe the fractal properties of PSD. The results demonstrate that the soil assembly with a larger pore structure tends to be a skeleton pore structure with strong fractal characteristics; the shorter the freezing duration is, the less damage caused by the freezing action; a larger pressure during freezing and thawing results in a lower fractal dimension value for thawing soil's structure, while a lower freezing temperature causes a larger fractal dimension of frozen-thawed soil.