An Investigation of the Influence on Compacted Snow Hardness by Density, Temperature and Punch Head Velocity

Snow, as an important component of the cryosphere, holds a crucial role in the construction of polar infrastructure. However, the current research on the mechanical properties of snow is not comprehensive. To contribute to our understanding of the mechanical behaviors of snow in cold regions, uniaxial compression tests under step loading were performed on the snow. With the Maxwell model as the basis, different temperatures, densities, and loading rates were set to establish constitutive equations of snow. The changes in the elastic modulus and viscosity coefficient of snow with respect to three variables were investigated. The results show that the loading rate has no obvious effect on the elastic modulus and viscosity coefficient of snow. Both the elastic modulus and viscosity coefficient of snow follow an exponential function with respect to density, with an increase in density, resulting in a higher value. As temperature decreases, the elastic modulus and viscosity coefficient initially decrease and then increase, whereas no specific functional relationship between them was observed. Additionally, a new constitutive equation considering snow density is derived based on the Maxwell model.

Section: Viscosity Coefficientmentioning

confidence: 99%

Study on the Constitutive Equation and Mechanical Properties of Natural Snow under Step Loading

Han,

Yang,

Liu

et al. 2023

“…The deformation of the ice matrix mainly led to a reduction of the pore space and an increase in coordination number, while metamorphism mainly affected the grain and bond sizes. Zhao et al [22] found that density is positively correlated with the hardness of compacted snow, and its sensitivity and significance to the compacted snow hardness are the greatest. During the winter of 2007-2008, Arakawa et al [23] measured the specific surface area per unit snow volume and intrinsic permeability of naturally deposited dry snow in Hokkaido Prefecture, Japan, and found that the correlation between specific surface area per unit mass and intrinsic permeability could be used to clearly distinguish the snow types.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Morphology of Snow Crystal Particles and Its Influence on Compacted Snow Hardness

Hu,

Li,

et al. 2024

Self Cite

In their natural state, snow crystals are influenced by the atmosphere during formation and multiple factors after landing, resulting in varying particle sizes and unstable particle morphologies that are challenging to quantify. The current research mainly focuses on the relationship between the porosity of compacted snow samples or qualitatively describes snow crystals and their macroscopic physical properties, ignoring that the significant differences in the morphology of snow crystals also affect their physical properties. To quantitatively evaluate the morphology of snow crystals, we employed optical microscopy to obtain digital images of snow crystals in Harbin, utilizing the Sobel and Otsu algorithms to determine the equivalent particle size and fractal dimension of individual snow particles. In addition, the hardness of snow with a density of 0.4 g/cm3 was measured through a penetration test, with an analysis of its correlation relative to particle size and fractal dimension. The results indicated the fractal dimension as an effective parameter for characterizing particle shape, which decreased rapidly over time and then fluctuated within the range of 1.10 to 1.15. During the initial period, natural snow crystals broke down rapidly, leading to an increase in the percentage of natural snow crystals with an equivalent particle size of 0.2–0.4 mm up to 51.86%. After three days, the sintering effect between snow crystals was enhanced, resulting in an even distribution of the equivalent particle size. Finally, multiple linear regression analysis showed a positive correlation between compacted snow hardness and fractal dimension, with a negative correlation between compacted snow hardness and equivalent particle size. These findings offer valuable technical support and data reference for exploring the relationship between snow’s mechanical properties and its microscopic particle shape.

“…The thermal characteristics and mechanical indices of snow are crucial parameters to be considered in cold-region science and engineering. The process of how snow evolves will undoubtedly be significantly impacted by changing climate conditions as global warming progresses [4,5], requiring a careful examination of snow mechanics and snow hazard issues [6][7][8][9][10]. In the future, a crucial strategy for dealing with snow science and snow risks will be to link the microstructure and apparent physical properties of snow.…”

Section: Introductionmentioning

confidence: 99%

Research on the Evolution of Snow Crystal Necks and the Effect on Hardness during Snowpack Metamorphism

Wei,

Lu,

et al. 2023

Self Cite

To study the snow microstructure at various metamorphism times and extract the snow neck area, a constant density (200 kg/m3) snow metamorphism experiment was conducted. The findings show that the neck region is mostly influenced by temperature, sun radiation, snow density and specific humidity, with wind speed having little effect. Additionally, we developed a multiple linear regression equation for the neck area under atmospheric forcing: “S = 288T + 2E + 189ρ + 12,194V − 20,443RH − 42,729”. This equation accounts for solar radiation (E), temperature (T), snow density (ρ), specific humidity (RH) and wind speed (V). Notably, the above five factors can account for 84% of the factors affecting the neck area, making it a crucial factor. The relationship between snow hardness and neck area is correlated at 71%, and in later stages of metamorphism, the correlation may increase to 91%. Based on the neck area, the following hardness value prediction is made: “H = 0.002764S + 67.922837”. This study documents the growth variations in the neck region of the metamorphic snow cover and elucidates the process by which outside factors impact the microstructure and macroscopic physical characteristics of the snow cover.