Abstract
The model of the tyre - soil system for predicting unit pressure of the tyres, rut depth and soil compaction in the rut caused by the tyre on the basis of pressure-plate sinkage theory which included the spherical contact area between the tyre and the soil was developed. The new model included many tyre and soil parameters and determined relations among them. It analysed the effect of the following factors: shape of the contact area determined with two authors methods, parameters of the tyre deflection on the soil at wheel movement and on the hard surface with wheel stopped, average unit pressure of the tyre and unit pressure acting on rut bottom, a modified equation of the pressure-plate sinkage theory, on the accuracy of the tyre-soil model in this work was examined. This analysis was made on the basis of empirical research and computer calculations using new computer programs elaborated for various variants of the tyre - soil model. Many parameters needed for this analysis were obtained in the field investigation carried out with application of new authors methods and measuring apparatus.