An experimental investigation on the strength and failure behavior of freshwater ice rubble

Abstract

Ice ridges are common features in Arctic and sub-Arctic regions. They are large accumulations (typically 5-30m) of ice rubble formed due to compressive or shear forces in ice cover. Understanding the deformation behavior and strength of ice rubble is key to estimating ice ridge loads on offshore structures. Medium-scale punch tests were conducted at C-CORE’s Cold Room facility to measure and observe the strength and failure behavior of freshwater ice rubble. A custom-built punch box measuring 3.05m in length and 0.94m in width and height was used to perform the tests. The box walls were made from Plexiglas so that failure mechanisms could be observed. Ice rubble beams of nominal thickness 50cm were produced by placing randomly sized ice pieces into the punch box, filled with water at its freezing temperature. After a specified consolidation time and rubble confinement, the ice rubble beam was deformed by pushing a platen vertically downwards though the center of the beam until failure. In this study the effects of consolidation time, pressure confinement, sintering process and small ice block dimensions on the strength and failure behavior of freshwater ice rubble beam were investigated. Results showed that the failure behavior of the ice rubble beam is controlled by the degree of freeze bonding between the blocks.