Geology Reference
In-Depth Information
Figure
4.3.
Schematic illustration of two mineral soil particles with ice and water: (a) general
conditions for segregated or pore ice formation in freezing soil; (b) growth of pore ice; (c) growth
of segregated ice
+
frost heave.
commonly develops in coarser-grained material, often sand and gravel, where it is harder
for the tension of cryosuction to be maintained in the correspondingly larger soil inter-
stices. These sediments are termed “non-frost-susceptible” and are used as aggregate
in building and for construction purposes, or wherever ground heaving needs to be
minimized.
Under certain conditions, apparently non-frost-susceptible materials may contain large
segregated ice lenses. This is commonly explained by saturated conditions associated with
pore-water expulsion ahead of the freezing plane.
4.2.3. The Frozen Fringe
The frozen fringe refers to the transition zone in a freezing, frost-susceptible soil that lies
between the warmest isotherm in which ice exists in pores and the isotherm at which the
warmest ice lens is growing (Miller, 1972). The concept was introduced to accommodate
the fact that freezing of soil moisture does not occur instantaneously at 0 °C. It was sub-
sequently developed by geotechnical engineers interested in predicting frost heave (Konrad
and Morgenstern, 1983). The freezing front refers to the downward-advancing boundary
