PERFORMANCE OF SOILS UNDER TIRE LOADS. REPORT 5. DEVELOPMENT AND EVALUATION OF MOBILITY NUMBERS FOR COARSE-GRAINED SOILS
Technical rept. Nov 1963-Mar 1965
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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This study examined the effects of tire deflection, tire geometry, wheel load, and soil strength on the performance of coarse-grained soils subjected to moving tire loads. Mathematical expressions were developed that combine the independent tire-soil and system parameters and relate them to the performance coefficients. A combination of independent parameters was developed from single-wheel laboratory tests. This expression, referred to as the sand mobility number, is shown to account for the combined effects of soil strength, tire section width and diameter wheel load, and tire deflection on wheel performance as measured by the performance coefficients. A multiple-pass analysis was conducted to illustrate that performance on the second and third passes also could be related to the sand mobility number, although the relation was not the same as that for the first pass. It was shown in a similar fashion that the performance of vehicles on coarse-grained soils could be predicted using a relation based on the sand mobility number.
- Soil Mechanics
- Surface Transportation and Equipment