Soil Deformation beneath a Wheel during Travel Repetition

To elucidate the phenomenon of the soil compaction observed during actual machine operation, a model wheel was traveled repeatedly and the subsequent soil deformation was analyzed. As repetitive travel progressed, soil particles drew similar trajectories with accompanying changes in the size and shape of the trajectories leading to the formation of spiral-like patterns. The changes depended on traveling slip and depth of the soil layer. The void ratio increased in with repetitions in the shallow layers, but decreased in the deeper layers. The change in void ratio in high slip conditions was larger than those in low slip conditions, indicating that repetitions in high slip caused more deformation and compaction than did those in low slip.