- May 2017
Hugh M. French, a member of the department of geography at the University of Ottawa, states that “nowhere has the frost heave problem been more critical than in the recent design of proposed chilled buried gas pipelines in Arctic regions” in his article entitled “Periglacial Geomorphology in North America: Current Research and Future Trends.” These chilled buried gas pipelines must function under extremely harsh conditions. They will be exposed to sub-zero temperatures in Arctic regions. Any water and vapor will “migrate towards the pipe” causing a frost bulb to form. This frost bulb will lead to the formation of an ice lens or numerous ice lenses which will cause frost heave around the chilled buried pipe (French, 1987). There are currently many techniques to attempt to predict the behavior of a buried pipeline that experiences frost heave. One such attempt to describe this phenomenon was proposed by Selvadurai and Shinde, both members of the American Society of Civil Engineers, in which they describe a detailed model of a frost heave zone caused by its associate frost bulb. They base their model off of the “heave of a frost bulb zone that develops around the pipeline as it transmits its contents such as chilled natural gas” (Selvadurai & Shinde, 1993).
French, H. M. (1987). Periglacial Geomorphology in North America: Current Research and Future Trends. Ecological Bulletins, 5-16. Selvadurai, A. P., & Shinde, S. (1993). Frost Heave Induced Mechanics of Buried Pipelines. American Society of Civil Engineers, 1929-1951.
Before the understanding of frost heave, there was a widely held belief that rocks and stones could grow and multiply. Stones were believe to grow from small pebbles. These stones then rose to the surface of the ground. Another belief was that stones were the offspring of “mother-stones” or “breeding-stones.” Today, it is known that this motion of stones moving upwards toward the surface of the ground is due to frost heave. Frost heave occurs when water in soil or rock freezes and thaws in a cyclic process. This causes an upward movement of the surface of the ground due to the freezing of water underneath. Geologist Stephen Taber from the University of South Carolina proved through extensive research that “it was not expansion, but rather the formation of ice lenses by segregation of water from the soil as the ground freezes that is the principal cause of frost heave.” He also showed that liquids other than water can also cause frost heave. The direction of heave is governed by the growth of ice lenses. Ice lenses form perpendicular to the direction of heat flow, so it is not always the case that frost heave occurs in the path of least resistance (Manz, 2011).
Manz, L. (2011). Frost Heave. Geo News, 18-23.