Four scaled centrifuge modeling experiments of thaw-related mass movement processes are described. Experiments were conducted at 1/10 and 1/20 scale in the Cardiff Geotechnical Centrifuge. Soil temperatures during thaw, pore water pressures, volume strain (thaw settlement) and shear strain were recorded. Pre-failure creep deformation (gelifluction), mudflow and translational landsliding were simulated. Contrasting patterns of porewater pressure variation in the slopes formed of silt and those formed of overconsolidated silt clay are described. The more permeable silts display a rapid rise in pore pressures immediately following thaw, with gradual dissipation of excess pressures as thaw consolidation proceeds. The low permeability clay soil shows repeated thaw-induced increase in pore pressure, separated by pulsed discharge events causing abrupt falls in the recorded pressures. Water escape may be facilitated by thaw softening of the clay, and the presence of discontinuities left by ice lenses. Such water escape mechanisms may have implications if the thaw consolidation theory is used to analyze the stability of thawing low permeability soils.
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