Effect of soil properties and soil disturbance on frost heaving of mineral soil: a laboratory experiment

Abstract

A laboratory experiment was done to identify the properties that make a substrate susceptible to frost heaving. Tests were carried out on nondisturbed soil cores (fresh and dry) of Ae and B horizons from sand, loamy sand, and sandy loam in a freezing cabinet (–3.5 °C). Cores were continuously supplied with water from below. Freezing tests were repeated after soil disturbance (V-shaped furrow, 50% increase in surface area). The effects of texture, horizon, drying, and disturbance on frost heaving were tested using repeated-measures analysis of variance with soil elements (organic Al, organic Fe, inorganic Al, inorganic Fe, C, and N) and soil fractions (clay, fine silt, coarse silt, fine sand, and coarse sand) as covariates. The effect of horizon was as important as that of texture, and soil disturbance increased frost heaving. Disturbed fresh B horizon from loamy sand and sandy loam heaved the most (soil expansion >5% in height), whereas nondisturbed dry Ae horizon, regardless of texture, and nondisturbed dry B horizon from sand heaved the least (soil expansion <0.8% in height). Soil elements and fractions had an impact on frost heaving, especially organic Al, although it was of a smaller magnitude. Therefore, it is suggested that seedbeds or planting substrates be prepared by exposing the nondisturbed Ae horizon only, that is, without exposing or disturbing the B horizon.