Indentation of Model Scale Pressure Ridges with a Vertical Indentor

摘要

A series of ice tank experiments was performed where indentation of model scalepressure ridges was studied. One of the aims of the test program was to analyze the change in the ice ridge force on a vertical indentor as the ridge was allowed to consolidate. The model ice ridges were manufactured from 40 m x 40 m sheets of ice which were first broken into pieces and then pushed into a 40 m long pile. During a test, a 120 mm wide flat indentor was pushed through a ridge at five or six locations along its length and the force on the indentor was measured. The ridge was allowed to consolidate between the indentations. The consolidation was quantified by using the cold sum which is a function of temperature and time. Five ridges were tested. The data analyzed suggest that the ridge indentation force in this test series is comprised of three components; (1) the force needed to displace the ice blocks in the ridge, (2) the force needed to break the bonds between the ice blocks, and (3) the force needed to indent the ice blocks themselves. It is then natural that the indentation force was increasing with both increasing cold sum and increasing compressive strength of the ice.