Preconditioning of deep snowpack for off-road vehicle mobility

Abstract

This paper addresses several preconditioning techniques for strengthening a deep snowpack in order to support vehicular loadings. The criteria imposed on preconditioning a deep snowpack were: (1) only light commercially-available vehicles or equipment could be used, (2) preconditioning would only be applied to the snow surface and (3) any additives to be used should be easily acquired in remote areas. Viable preconditioning techniques were first evaluated in the laboratory using artificial snow. The techniques explored were surface loading (surcharging), heating and mixing with additives (sand and straw) followed by surcharging. The properties of the laboratory-preconditioned snow were evaluated primarily in terms of footing penetration resistance and Rammsonde hardness. Based on the laboratory results, preconditioning of a deep natural snowpack was carried out. Surcharging the snowpack was achieved by a BV206 Carrier. The preconditioning techniques studied were surcharging, heating and mixing with additives (salt and straw). Various ageing periods were imposed. The load-carrying capacity of the preconditioned snowpack was evaluated by multipasses of two wheeled vehicles (Iltis and 5/4 ton truck). The results indicated that a soft deep snowpack can be preconditioned to the extent that it can support multipasses of wheeled vehicles.