A Study of the Effects of Wet Surface Soil Conditions on the Performance of a Single Pneumatic-Tired Wheel

A test program was conducted to determine the effects of wet surface soil conditions on the performance of pneumatic tires. The surface soil conditions were of three types: (a) unflodded (as compacted), (b) flooded and undrained, and (c) flooded and drained. Most of the tests were conducted with one soil (fat clay) and one tire deflection (35 percent). All test tires were 6.00-16, 4-PR. Four tire surfaces, called tread patterns in this report, were tested: a smooth tire (i.e. no tread), a directional tread, a nondirectional tread, and a smooth tire with a traction aid. Test results showed that in soils exhibiting nonuniform soil-strength profiles, the type and extent of the nonuniformity largely controlled the tire performance. For a given wheel load, the loss of pull due to flooding, expressed as a percentage of the pull in the unflooded condition, was essentially constant for each tread pattern. The treated tires and the smooth tire with traction aid performed better than the smooth tire in flooded soil. In the unflooded soil, the tread pattern made a considerable difference in performance. Peak performance usually was attained at an optimum load, regardless of tread pattern or soil condition.