Prediction of Soil Stresses Beneath a Rigid Wheel

A finite element modeling technique is being de- difficult to measure and the rigid geometry permits the veloped as a management tool that can be used to determination of the direction of these stresses. A true predict and avoid excessive soil compaction. Values of three-dimensional device (such as an agricultural trac normal stress between a rigid wheel and the soil were tor tyre) is much more difficult to model because the obtained using an instrumented bar across the width direction of the stresses at the soil interface are of the wheel. These values were used to apply loads to the finite element model. A non-linear stress-strain relationship was used that shows that soil compaction is a function of both normal and shearing stress. The linear-elastic parameters, Young’s Modulus and Poisson’s ratio, are updated at small increments of load to follow the non-linear stress-strain relationship closely. Values of octahedral normal (mean normal) and major principal stress are predicted accurately in some situations but not at the high load condition in an initially uniformly loose soil profile. 1