Rubble macro-porosity of level ice accumulation on wide sloping offshore structures

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Journal Title
Journal ISSN
Volume Title
Insinööritieteiden korkeakoulu | Master's thesis
Date
2018-09-24
Department
Major/Subject
Mcode
ENG216
Degree programme
Nordic Master's Programme in Cold Climate Engineering
Language
en
Pages
67 + 37
Series
Abstract
When level ice fails against sloping coastal or marine structures, rubble accumulation has significant effect on the ice load. The weight of the rubble, or the buoyance force of the rubble if the rubble is accumulated underwater, is a function of ice density and rubble porosity. The rubble porosity is usually unknown and is set as 0.3. The purpose of the report is to evaluate how different parameters affect the rubble porosity. A series of test were conducted at HSVA ice tank by RITAS campaign in 2012 to investigate level ice interacting with downward sloping structures. The tests were conducted with varying ice thickness, ice density, ice strength and ice velocity. Data from this test is examined to find how the varying conditions influence rubble porosity. Since the porosity of a material is mainly determined by particle size distribution, the length and thickness of the ice blocks in the rubble are measured. Ice breaking length is also measured because it may be an indicator of ice block length. Several approaches are used to measure ice length and rubble porosity. The results from different approaches are compared. Based on the experimental data, formulas to estimate block size and rubble porosity are proposed.
Description
Supervisor
Polojärvi, Arttu
Thesis advisor
Høyland, Knut
Keywords
ice rubble, macro-porosity of level ice, sloping structures, cold climate engineering
Other note
Citation