Spatial-temporal variability of static ice forces

The spatial and temporal variability of ice forces near dam faces have been studied over three winter seasons. This paper introduces the project and explores some of the preliminary results acquired to date. Field measurements included ice deformations rates calculated using a robotic total station and image analyses. In-ice stresses were determined using in-situ stress gauges places at various locations and depths. Ice pressures against the wall were measured directly at four elevations and at up to 11 locations. While ice displacement measurements followed a fairly regular pattern associated with thermal events and water level fluctuations, in-ice stresses behaved in a spatial-temporal chaotic manner – sometimes in phase with ice displacement and sometimes not. Measured pressures against wall face showed correlations with temperature changes and water level fluctuations but were also fairly chaotic. This article presents some reflections on the nature of the observed spatial-temporal variability.