Prediction of load carrying capacity of deep snow by rammsonde hardness

Abstract

The ability of a natural snowpack to support the weight of a vehicle is often difficult to predict. Misjudgement of the load-carrying capacity of a snowpack may result in hang-up failure (i.e. immobilization) or a degree of high sinkage producing low tractive efficiency. The load-carrying capacity of snow media may be predicted from measurements of vane and cone resistance in the various snow types. In a remote region where off-road vehicles normally travel, a portable, easy to operate, field device such as the Swiss Rammsonde is shown to provide a practical and alternative measure of snow strength. In addition, Rammsonde hardness may be correlated with vane and cone resistance parameters and provide input to a footing pressure-displacement relationship, thereby serving to indicate vehicle flotation or sinkage.