Behavior of Snow Containing an Ice Lens under Compressive Loading

Abstract. In order to understand the effects of strain rate on the mechanical response of snow containing an ice lens perpendicular to the loading direction, specimens with and without ice lenses were compressed at several different rates from 4 x 10^-4 to 1.2 x 10^-2 s^-1. It was found that snow columns with an included ice lens follow the same behavior as homogeneous snow for the range of strain rates tested, the sole difference being a six-fold increase in stress at a given strain when an ice lens is present. For all samples, low strain rates (4 x 10^-4 to 1.2 x 10^-3 s^-1) resulted in a smooth steady increase in stress with increasing strain, whereas at high strain rates (4 x 10^-3 to 1.2 x 10^-2 s^-1) two loading regimes occurred; up to ~20 % strain stresses minimally increased, while higher strains led to a more rapid stress increase. Snow columns both with and without an ice lens showed the highest resistance to loading at intermediate rates (2.1 x 10^-3 to 3 x 10^-3 s^-1) which allowed for reconfiguration of the ice particles whilst inducing pressure sintering to strengthen existing bonds. Stress differences between aged and fresh snow were distinct but not as large as those between ice lens-containing and homogenous snow, indicating that ice lenses have a higher contribution to snow strength than sintering alone.