Mesomechanical analyses on the failure mechanism of the snow cluster assembly under direct shear test using discrete element method

Abstract

The shear strength of snow is an important parameter for assessing the safety of polar snow projects. To investigate the bearing and failure mechanisms of compacted snow during shear, a series of direct shear tests and corresponding discrete element simulations were conducted. The discrete element model was established using the “falling snow method” to simulate snowflake generation, landing, compression, and sintering. The contact model parameters were determined based on tested data, and simulated strengths under direct shear matched the experimental results. Results indicate that snow with a density below 450 kg·m⁻³ primarily fails through bending, while those at or above this density mainly fail by shearing. As density and normal stress increase and sintering decreases, the percentage of bond shear failures increases, while bond bending failures decrease. The contribution of bond contact force to shear stress was greater than that of frictional contact force, with normal contact force contributing more than tangential contact force. At shear’s end, the bond contact force contribution in high-density snow was 66.9 %, lower than the 85.3 % in low-density snow. Additionally, tensile zone breakage consistently exceeded that in the compressive zone.