Abstract
The deterioration of soil properties as a result of repeated impact of undercarriage of tractor units leads to the reduction in crop yields. Increasing of soil density caused by the impact of movers of tractors and agricultural machines results in increase of soil hardness by 2-3 times. To forecast the indices of undercarriage impact on soil taking into account the type and condition of soil fertility, as well as to determine the promising ways of improvement of undercarriages’ designs and their agro-ecological characteristics, it is necessary to substantiate the regularities of accumulation of repeated soil settlements under the impact of undercarriage. It is also necessary to determine the regularity of rise of settlement deformer under repeated soil load. The deformation at each subsequent soil loading is followed by stress rise in the contact zone as compared to the previous one. This is due to the increase in load intensity under repeated deformations, in particular due to the reduction of contact area of wheels with soil during repeated passing of tracks. This paper observes some dependencies which allow to determine the deformation of soils with different physical and mechanical properties under various operating conditions and parameters of undercarriages of tractor units. For the soil with high degree of compaction, the depth of track should be reduced by increasing the number of axles of undercarriage. For the moist soil with low degree of compaction, the movers with larger width of wheels should be used to reduce the depth of track.