Rubble Ice Transport on Arctic Offshore Structures (RITAS), Part III: Analysis of Model Scale Rubble Ice Stability

A series of tests on model ice rubble were conducted at the Hamburg Ship Model Basin (HSVA) in Hamburg, Germany. This paper is the third out of four papers from the RITAS experiments. The three others are “Rubble Ice transport on Arctic Offshore Structures (RITAS), Part I: Model scale investigation of level ice action mechanisms”, “Part II: 2D model scale study of the level ice action”, and “Part IV: Tactile sensor measurement of the level ice load on inclined plate”. Ice rubble properties were investigated both in water and air. For submerged tests a box with 0.93×0.97×1.1 m dimensions of internal volume was filled with rubble material and tilted afterwards until failure occurred. For dry tests a rectangular board 2×1.3 m with support ledges along the long dimensions was used for rubble ice pile construction and subsequent tilting. During both procedures initial geometry of rubble piles and angles of inclination leading to failure were measured. Considering ice rubble as a bulk material which obeys Coulomb’s failure criterion and that the repose angle of the pile equals to the friction angle (initially zero cohesion is assumed) the cohesion component of shearing strength can be estimated.