Cyclic Behavior of Iron Ore Fines on Board Bulk Carriers: Scale Model Analysis

Abstract

Solid bulk cargoes have been known to liquefy in the holds of bulk carriers since the loss of the Bengal in 1910. Because of the increased demand for iron ore fines over the past 20 years, export industries have experienced further incidents where liquefaction of the cargo was the suspected cause. The objective of this study was to develop a scale model of bulk carrier hold in order to investigate the variability of the physical properties of iron ore fines, which govern the liquefaction potential under cyclic loading. Additionally, by associating the theory of liquefaction of partially saturated soils to the cyclic behaviour of the samples, the apparent shear strength of the samples can be determined. During this study a scale model and an iron ore fines plunger were developed and utilised. The physical properties of the samples of iron ore fines were monitored during the scale model test, and the point at which moisture migration began to occur was determined. The boundary where the material showed a significant loss of shear strength, referred to as the critical failure curve, was also determined using the iron ore fines plunger. After consistent results were shown using both methods, the moisture content at which the sample was considered potentially liquefiable was concluded and compared with the results from the current test method used to reduce liquefaction incidents on bulk carriers.