Multi-Pass Rutting Study for Turning Wheeled and Tracked Vehicles

In this article, the effects of multiple vehicle passes and turning maneuvers by wheeled and tracked vehicles on rutting are discussed. Field tests were conducted at Fort Riley in August 2008 using an M1A1 combat tank, an armored personnel carrier (APC), a heavy expanded mobility tactical truck (HEMTT), and a high-mobility multi-purpose wheeled vehicle (HMMWV). These vehicles were operated in spiral patterns to evaluate the effect of different turning radii. Along each spiral in the same rut, each vehicle was driven up to eight passes. A vehicle tracking system (VTS) mounted on each vehicle utilized a Global Positioning System (GPS) to determine the vehicle dynamics (velocity and turning radius). As expected, compared to a single pass, results show that soil deformation and compaction increased with the increase in the number of passes. Multiple passes and turning maneuvers by vehicles resulted in rut depth increases in the range of 65% to 548%. The results of this study also confirmed that the multi-pass coefficient (a = 2) is appropriate to predict multi-pass rut depth for turning vehicles in loose soils.