frostheave

Frostheave is a geomorphological and civil engineering term describing the upward movement of soil, pavement, and embedded objects caused by frost action in cold climates. The effect is most pronounced in frost-susceptible soils, such as certain clays and silts with high moisture content, where the combination of freezing temperatures and water migration leads to ground uplift and surface deformation.

During freezing, water in the unfrozen part of the soil migrates toward the advancing freezing front by capillary action and pressure gradients. As temperatures fall, sheets of ice known as ice lenses form within the soil, expanding as they grow and pushing surrounding soil upward. The process can occur over seasonal cycles, producing gradual or abrupt heave. When temperatures rise, the ice melts and some of the relief is lost, but repeated cycles can cause cumulative damage.

Frostheave commonly affects infrastructure such as roads, sidewalks, building foundations, and buried utilities. Local depth of frost penetration and the availability of moisture influence the severity of heave. The severity is often higher in poorly drained or inadequately compacted backfill, and in areas with high seasonal temperature fluctuations.

Mitigation focuses on reducing frost susceptibility and moisture availability. Strategies include improving drainage, using frost-stable backfill or nonfrost-susceptible materials, insulating subgrades, eliminating vegetation that retains moisture, and designing with proper slope and drainage to minimize water collection. In construction, careful compaction and quality control help reduce susceptibility.

Frostheave is closely related to, and sometimes used interchangeably with, frost heave in the literature.