Factors affecting ice loads during the rubbling process using a 2D FE-DE Approach

Simulated ice rubble pile formation process and ice loads on wide sloped structures are studied. Since the ice rubble accumulation on a structure affects the ice failure process, the calculation of the total ice load is not a simple task. The understanding of the ice rubbling process and the calculation of the ice loads on structure are important challenges for design and safe use of marine structures in ice covered waters. A two-dimensional combined finite-discrete element method was developed and applied to numerical simulations of ice rubbling loads. With the method used, the formed ice rubble piles were also able to be studied as a granular assembly. This enabled an insight to the processes and phenomena occurring in the rubble pile during ice rubbling. The developed method was validated with both model and full scale experiment data using reported rubble pile properties and load responses on structures. The phenomena during peak load events of the simulated ice rubbling process indicated that the rubble pile was loaded at the instant of a peak load in a manner that a part of the pile was pushed upwards. Numerical experiments on parameter effects on peak ice loads on sloping structures showed interaction between the parameters, indicating that the parameter effects cannot be considered separately. An explanation for the observed vertical pressure distribution on a sloping structure was given with force chains discovered from the loose ice rubble pile. Also, the load drop on the structure was linked to the buckling of these force chains. Hence, to be able to predict the ice loads on sloped structures with a loose rubble pile in front, the force chains and their buckling behavior should be understood.