Cranfield University

Introduction
a) the soil compaction of multi wheel systems compared to track data from Figure
1. Hence answering the question whether multi-wheel systems have similar soil
compaction characteristics as tracks
b) the influence of time of contact on soil compaction parameters to illuminate the
effect of reduced traffic speed on increased soil compaction in headlands and to
simulate a long contact time as it occurs with a track
c) the additional soil compaction caused by a rear tyre after the passage of a tyre
or a track
d) the soil compaction characteristic caused by tracks. In particular answer the
question “what causes the dense layer close to the surface detected by Ansorge
(2005, a)?”
e) the soil density increase of a wheeled combine harvester at 11 t in comparison
to a modern one on tracks at 33 t
f) the draught force of a subsoiler to loosen the soil after the passage of a tracked
and a wheeled machine
g) the vertical soil failure found by Ansorge (2005, a)
3. The full size combine studies will be conducted in field conditions on different soil
types.
4. The effects on soil properties to be determined by changes in:
a) Soil displacement
b) Penetration resistance
c) Rut characteristics
d) Dry bulk density
e) Pressure distribution in the soil
Hereby each measurement is replicated three times.
5. Data analysis and explanation of results.
6. The further development of the compaction prediction models of Smith /
O’Sullivan / van den Akker including triaxial cell tests and plate sinkage tests to
derive virgin compression line parameters for the prediction of soil displacement.
Ph.D. Thesis Dirk Ansorge (2007)
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