Mechanical behaviour and structure of snow under uniaxial tensile stress

Abstract

The mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10^–8to 3.1 × 10^–4ms^–1and snow density 240-470 kg m^–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10^–5s^–1, the maximum strength increased with decreasing strain-rate but below 10^–5s^–1it decreased with decreasing strain-rate.