Influence of turning radius on wheeled military vehicle induced rut formation

A rut is a depression or groove formed into the ground by the travel of wheels and tracks. Ruts can cause severe influences on soil and vegetation, and reduce vehicle mobility. In this paper, rut depth and rut width were used as the main indicators to quantify a rut. A new indicator, rut index, was proposed, combining rut depth and rut width. A Light Armored Vehicle (LAV) and a High Mobility Multi-purpose Wheeled Vehicle (HMMWV) were used for testing the influence of turning radius on rut depth, rut width and rut index. The LAV and the HMMWV were operated in spiral patterns at different speeds. Differential GPS data for the vehicles were collected every second during the spiral. Rut measurements were manually taken every 4–7 m along each of the spiral tracks. The results of field tests indicate that rut depth, rut width and rut index increase with the decrease of turning radius, especially when turning radius is less than 20 m. Velocity influences rut formation for the LAV but not HMMWV.