The Influence of Soil Surface Conditions on the Traction of Wheeled and Tracked Military Vehicles

Abstract : The purpose of this study was to investigate a means of predicting the loss in vehicle traction associated with soil type and rainfall amounts. Firm soils were used which allowed only negligible vehicle sinkage. The soil types investigated were CH, CL, ML, SC, SM, and SP soils as classified by the Unified Soil Classification System. Incremental simulated rainfall was applied in 1/4-in. increments up to a maximum of 1 in. Eighty traction tests were used for this study with three state-of-the-art military vehicles. Results of this study indicate that the greatest loss in traction for most soil types is between the dry surface condition and 1/4 in. of rainfall. The more clay fraction in the soil, the more traction loss can be expected, with rainfall and the traction loss more appreciable for the wheeled vehicles than with the tracked vehicle.