Rates and processes of periglacial solifluction: An experimental approach

Cold room physical modelling of periglacial solifluction processes on an experimental slope of 12 degrees is described, and data on soil temperatures, surface frost heave, thaw consolidation, downslope soil movement and porewater pressures over seven freeze-thaw cycles are presented. These data are analyzed in the context of laboratory determination of the rheometry of the experimental soils at high moisture contents. It is concluded that the observed thaw-induced solifluction represents pre-failure soil shear strain and results from loss of strength due to the combined effects of raised porewater pressures during thaw consolidation and upward seepage pressures as water hows towards the surface away from the thaw front. An investigation of the rheometry of thawing soils offers the prospect of an analytical model to predict rates and depths of periglacial solifluction. (C) 1997 by John Wiley & Sons, Ltd.