Formation of Frost Heave

Question

Explain the mechanism in the formation of Frost Heave?

Answer 1

Earlier, it was believed that the formation of frost heave was associated with the volumetric expansion of soil water which gets changed from liquid to solid state. However, increase of volume of changes in states for water at zero degree Celsius is only about 9%.

The mechanism of frost heave is best described by the formation of ice lenses. When the weather is cold, ice lenses develop in freezing zone in soils where there is a sufficient soil water supply. Particles of soil are surrounded by a water film, this separates the soil particles from the ice lenses. The moisture of soil particles gets absorbed by the ice lenses on top of the soil and in turn water is acquired from other soil pores to replenish the water loss to ice lenses. This process goes on and results in pushing up of the soil on top of the lenses and consequently the formation of frost heave.