Behavioral analysis of seabed slope subjected to ice gouging

Abstract

Ice gouging is a phenomenon that occurs when ice drifts to shallow depths due to current, wind and tides, thus resulting in a large deformation. Many previous studies have conducted numerical analysis based on centrifuge model experiment to understand the mechanism of ice gouging. Strain softening and rate dependence are the two important factors that influence ice gouging. However, the effect of these two important factors on the seabed subjected to large deformation was not considered in previous studies. Therefore, in this study, these factors are simulated, and the occurrence of large deformation in soil due to ice gouging is analyzed. In addition, numerical modeling based on two cases from among knowledge gained via various centrifuge model experiments is implemented. To simulate the large deformation of the soil, return mapping algorithm is applied to the ABAQUS subroutine VUMAT in conjunction with the formulas that define strain softening and rate dependence. These factors are reflected in ice gouging simulations and the consistency is reviewed by comparing and analyzing the results of the centrifuge model experiments implemented in previous studies. Based on this, the kinetic energy of ice keel is defined and a subroutine expressing kinetic energy reduction according to seabed soil resistance is additionally reflected. In addition, this method is applied to seabed slope in cold region to analyze the behavior of the slope.