Tests on Coarse-Grained Soils with Self-propelled and Towed Vehicles, 1956 and 1957

Self-propelled, towing, and towed tests of several military vehicles were conducted on coarse-grained soils to correlate vehicle performance with strength cone index and moisture condition of the soil, and vehicle characteristics. Vehicle performance for self-propelled vehicles is expressed in terms of immobilizations and nonimmobilizations and ability to pull draw-bar loads for towed vehicles, in terms of towing-force requirements. Single self- propelled wheeled vehicles were tested on undisturbed coral and volcanic sands on Pacific islands, and on quartz sand desert and beach in the United States. Towing tests were conducted on harrowed sand at Yuma, Arizona towed-vehicle tests were conducted on disturbed and undisturbed sand at Camp Lejeune, North Carolina. Prinicipal conclusions are a performance on single self-propelled vehicles can be expressed in cone index-slope climbing ability terms b wet sands are more trafficable than dry-to-moist sands c performance, as defined by the cone index-slope climbing curves, is the same regardless of sand source quartz, volcanic, or coral or location beach or desert d towing ability of self-propelled vehicles wheeled and tracked on harrowed sand slopes can be computed with reasonable accuracy from performance measurements obtained in tests of the respective vehicles on level harrowed sand and e towing-force requirements of wheeled trailers can be correlated with cone index and tire pressure.