Large-scale shear test of brash ice

A large-scale shear apparatus has been originally developed and built to test the mechanical properties of coarse grained material. It was used to evaluate the shear behaviour of brash ice. The brash ice blocks were collected at Lulea harbour in two separate measuring campaigns in March 2020 and March 2021. The shear cylinder was loaded with brash ice in Lulea port in two different locations for the two test campaigns, and the displacement controlled shear tests were conducted. A vertical actuator was used to set a constant normal load and then a horizontal actuator was used to move the shear swing. In this setup, time, forces, and displacements were recorded at the forward and return stroke of the horizontal actuator. In total 6 shear cycles on two brash ice samples with axial stress of 4.8 kPa, 2 kPa and 1 kPa were performed. The test data was analysed to determine the relationship between shear stress and shear strain. The macro-porosity and confining axial force were found to be the most influential factors in determining the strength and deformation of the brash ice. Furthermore, an attempt has been made to estimate a few parameters of a material model known as the Continuous Surface Cap Model.

Automated summary

A large-scale shear apparatus was developed to test the mechanical properties of coarse grained material, and was used to evaluate the shear behavior of brash ice. By conducting shear tests on brash ice samples with different axial stresses and analyzing the test data, the relationship between the strength and deformation of brash ice and macro-porosity and confining axial force was determined.