Magnetic resonance imaging as a tool for investigating frost heave dynamics: a new experimental setup and application

Frost heave in frozen soils is a critical geotechnical phenomenon driven by thermal gradients, moisture migration, and ice formation. Understanding this process is essential for ensuring infrastructure stability in cold regions. While previous studies have contributed to understanding frost heave mechanisms, they provide limited insight into local changes within the sample during freezing, particularly regarding the distribution of unfrozen water content. To address this gap, this study introduces the development of a new experimental setup, specifically designed for magnetic resonance imaging (MRI) to investigate the frost heave behavior of sandy soils. MRI was used to track the distribution of the local amount of unfrozen water content during freezing. Frost heave tests were conducted on saturated sandy soils. The testing program and the experimental results are presented and discussed, focusing on the freezing point, temperature evolution at different elevations within the specimens, water uptake monitoring, local water content distribution, and frost heave progression. This new apparatus offers a realistic laboratory approach to studying the effect of freezing and thawing on soils.