Effects of vertical load and inflation pressure on tire-soil interaction on artificial soil

Instrumented single tire soil bin testing was conducted on a rigid surface and artificial soil by vertically loading a radial tire (LT235/75R15) to two tire vertical loads (6 kN and 8 kN) inflated to three levels of tire inflation pressure (179, 241, and 283 kPa). Lowering the tire inflation pressure by 37 % resulted in 26 % (6 kN vertical load) and 39 % (8 kN vertical load) greater contact lengths (P < 0.05). The 2-D contact area on artificial soil (initial bulk density of 1.51 Mg/m³) was significantly affected (P < 0.05) by tire inflation pressure for each load case. Increasing the load significantly affected the tire’s contact length on soil (P = 0.0010); however, tire inflation pressure did not significantly affect the contact length on soil (P = 0.0609). Soil rut depth and tire-soil deformed volume were not significantly affected by vertical load and tire inflation pressure. Measured tire contact area on soil surface was 3.3 times the contact area on the rigid surface, suggesting tire-soil interaction interface properties on deformable soil are better than using the gross flat plate for evaluating low ground pressure tire technology effects on traction and reducing soil compaction.