ABSTRACT
Intensification of crop rotation and advancing mechanization are ever more coupled with compaction of the subsoil. In addition to field studies there is an increasing need for tools to evaluate effects of field traffic on soils at variable conditions of texture, density and moistening.
This paper describes the principle and application of a first version of a model that computes compaction of the subsoil due to field traffic. The model is based on the work of FRÖHLICH (1934) who started from the theory of Boussinesq for a point load on a isotropic semi-infinite solid mass. Starting from the horizontal and vertical stresses under wheels acting on the subsoil the model calculates the horizontal, vertical and shear stresses in a 3-dimensional space in the subsoil. From these results the principal and the mean stresses are computed. A concentration factor is incorporated in the model to account for the non-pure elastic behaviour of soils. On the basis of relationships between stress and bulk density for a particular soil, obtained from triaxial tests, the calculated stress distribution can be converted into a density distribution.
The model considers subsoil compaction only, because the model theory permits merely small deformations.
