Soil stress state determination under wheel loads

Two 6-directional stress state transducers were used to measure soil stresses beneath a moving tire in the soil bins at the National Soil Dynamics Laboratory. Principal stresses, stress invariants, and octahedral normal and shearing stresses were calculated from the measured stresses. The ratio of octahedral shearing to octahedral normal stress indicated high shearing action under the tire although the tire was developing no net traction.