HR: 1340h
AN: C13B-0282    [Abstracts]
TI: A coupled thermo-mechanical model of the differential frost heave
AU: * Nicolsky, D J
EM: ftdjn@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK 99775-7320 United States
AU: Tipenko, G S
EM: ffgst@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK 99775-7320 United States
AU: Romanovsky, V
EM: ffver@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK 99775-7320 United States
AU: Walker, D A
EM: ffdaw@uaf.edu
AF: Institute of Arctic Biology, University of Alaska Fairbanks, PO Box 757000, Fairbanks, AK 99775-7000 United States
AB: Research investigates cryoturbation processes in the Arctic tundra, and mechanisms that cause differential frost heave in the active layer. The project explores the influence of seasonal freeze/thaw cycles on the dynamics of frost boils north of the Alaska's Brook Range. The main question to be addressed is, "How changes in surface conditions such as vegetation, snow cover and climate affect the seasonal dynamics of water and heat within frost-boil systems?" A coupled thermo-mechanical model of the frost boil phenomena based on principles of thermodynamic equilibrium and continuum mechanics will be presented. The soil is treated as a heterogeneous fully saturated mixture of ice, water and soil particles, which obeys laws of elasticity for slow deformations in a porous media. The pore water migration towards the freezing zone and its consequent freezing are the main driving forces of the soil deformation. The model includes the heat and mass conservation laws, continuity equation, the Claiperon equation, and an empirical formula, which relates unfrozen water content to temperature. The basic system of equations is reduced to a computationally convenient set of coupled equations for temperature, liquid water pressure, porosity, and the velocity of soil particles in a three-dimensional domain with an assumption of cylindrical symmetry. A finite element method and an implicit scheme in time are utilized to construct a non-linear system of equations, which are solved iteratively.
UR: http://www.gi.alaska.edu/snowice/Permafrost-lab/
DE: 3210 Modeling
DE: 1823 Frozen ground
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting