Propriedades reológicas de solos antárticos afetadas por ciclos de congelamento e descongelamento

Abstract

The detailed study of the Antarctic soils is considered one of the priorities in this region, being fundamental for a better understanding of the functioning of terrestrial ecosystems and analysis of the possible effects of climate change. Understanding the mechanical behavior of the soil in relation to freezing and thawing cycles, which are increasingly frequent due to an increase in global temperature, is considered a key to understanding the effects of global warming. This research quantitatively evaluates the effect of freezing and thawing variations on the rheological properties of four soils in the marine Antarctica. In a rotating rheometer, the effect of one, five and nine freeze-thaw cycles was evaluated compared to soil without freezing, using the amplitude sweep test. We determined the rheological parameters strain in the linear viscoelastic interval (γLVE), shear stress at the end of the linear viscoelastic interval (τLVE), maximum shear stress (τmax), deformation at yield point (γYP), and storage and loss point flow modules (G’G” YP). The freeze-thaw cycles influenced the rheological properties of the soil. There was both an increase and decrease of the strain at the end of the linear viscoelastic interval (γLVE) and at the yield point (γYP), with differences between the sampled locations. The resistance and elasticity of the Antarctic microstructure show great variation between the types of soils, but a pattern of behavior was not found for the evaluated characteristics, where soils with different texture behaved similarly in some rheological properties.