A Grading Entropy Review of PSD-Based Frost Susceptibility Criteria

Particle size distribution (PSD) is recognised among geotechnical engineers as an informative soil descriptor, and often used to predict geomechanical behaviours. However, the effectiveness of PSD to characterise frost action is debatable. Existing criteria for assessing frost susceptibility have relied on traditional PSD descriptors, such as Cu, which depend on individual parameters (i.e., d(10), d(60)) which explicitly neglect the effect of fines and gravel content. In turn, it has been reported that fines content is critical in the formation of ice lenses. Grading entropy is a method which accounts for all the information in the PSD. In this work, normalised entropy coordinates are used to review PSD-based frost susceptibility criteria and assess whether alternative PSD descriptors can more successfully characterise frost action susceptibility. The effect of PSD (via grading entropy coordinates) on the development of frost heave is investigated using existing experimental datasets. The findings in this work highlight significant variability in the PSD criteria, suggesting that PSD alone is not a reliable indicator. However, examining experimental datasets indicated a clear effect of PSD using grading entropy coordinates for understanding the development of frost heave.