Cranfield University

Soil Compaction Models
surface stayed similar, but the characteristic with depth changed exhibiting a larger change
at the surface than at depth (below 400 mm) as expected.
Depth (mm)
0
100
200
300
400
500
600
700
800
Displacement (mm)
-20 0 20 40 60 80 100 120
Figure 86: Predicted sinkage for tracks using individual VCL
Claas Low Tension
Claas T12
Track Predicted 4 Rolls of 680
Unequal Weight
TrackVCLWORoller4Rolls of 680
Track VCLinclRoller4Rolls of 680
Unequal Weight
TrackVCLinclRoller4Rolls of 680
Unequal WeightHalfPressure
Subsequently halfing all inflation pressures put the line closer to the measured data. Using
the in-situ VCL of tyres and tracks made soil displacement with depth more linear which it
in reality is not. Thus the track specific VCL predicted the track at normal belt tension
most closely, although this is regarded as an outlier. It was not possible to predict the shape
of the soil displacement and particularly no residual soil displacement from the TerraTrac
measured at 50 bar belt tension, although rut depths agreed well.
Hence, to model tracks accurately the same methodology as previously developed for tyres
seems promising. However, to be able to evaluate different track types, “something else”
or some other methodology would have to be developed.
6.5 VCL from Plate Sinkage Data from Triaxial Cell
The section utilizes small scale plate sinkage experiments to gain an in-situ VCL with the
same methodology. This will further validate the in-situ approach as it is on a totally dif-
ferent scale, but using the same procedure. The plate sinkage method is explained in sec-
tion 2.3.2 and the contact patches which are used have also been used for the work de-
scribed later in Section 7.3. Similar to the soil bin a uniform soil density increase over the
Ph.D. Thesis Dirk Ansorge (2007)
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