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Abstract ABSTRACT The importance of undercarriage design with respect to its effect on soil density changes grows with the size of harvest machinery. Therefore this study elucidates the mechanics of soil displacement caused by different undercarriage systems of combine harvesters on soil. The soil displacement caused by different undercarriage systems at maximum working weight was measured by embedding tracers into the soil in both the soil bin laboratory and the field studies. The effects of different tyres, tracks, and whole undercarriage systems on soil density increase were significant. The results from whole machine systems were vali- dated with field experiments using fish-hooks for measuring displacement on a sandy loam and a clay soil. The draught force of a tine loosening the soil after the passage of whole machines was also investigated. With an increase in speed, soil density increase was reduced. The implement tyre evaluation emphasized the importance of tyre width, diameter, and inflation pressure on soil density increase. The evaluation of whole machine systems showed that the influence of rear tyre size on additional soil density increase is larger for wheeled than for tracked undercarriage systems. The strong layer at the surface from a track is able to carry the rear tyre without further compaction of the soil below leading to an overall soil displacement similar to a wheeled machine of 1/3 of the weight. The evaluation of different track systems emphasized the effect of the number of rollers on soil physical parameters. Variations in a high belt tension range showed only small effects. A novel approach was developed determining virgin compression line parameters in-situ from contact pressure, rut and working depth enabling an easy adjustment of a model to given soil conditions and a successful prediction of soil displacement for tyres. The in-situ approach can be used for tracks, but a different VCL results. The in-situ VCL was vali- dated with small scale plate sinkage tests and compared to results from triaxial cell testing. Results from triaxial tests showed that the VCL depends on the relation of major and minor principel stresses. Ancillary experiments were carried out to shed light on longitudinal soil movement and the influence of lugs and pressure history on soil displacement. In addition a new heuristic model involving load per perimeter length was tested and the “punching failure” of soil observed justified with theories from literature. Ph.D. Thesis Dirk Ansorge (2007) I
Abstract Ancillary experiments showed that the dense layer at the surface from the tracks originates from a backward soil movement limited to the uppermost 150 mm. The lug influence of both tyres and tracks was insignificant from 200 mm depth downwards. From heuristical data analysis the load per perimeter length was identified as an important variable. Peaked pressure history caused about 1/3 more sinkage than constant contact pressures. Ph.D. Thesis Dirk Ansorge (2007) II
Page 1: Cranfield University School of Appl
Page 5 and 6: Table of Contents TABLE OF CONTENTS
Page 7 and 8: Table of Contents 4.1.3 Analysis of
Page 9 and 10: Table of Contents 11.1.1.1 Comparis
Page 11 and 12: List of Figures and Tables Figure 3
Page 13 and 14: List of Figures and Tables Figure 1
Page 15 and 16: Nomenclature NOMENCLATURE Abbreviat
Page 17 and 18: Introduction 1 INTRODUCTION 1.1 Bac
Page 19 and 20: Introduction � Ansorge, D. and Go
Page 21 and 22: Introduction 1.2 Aim To elucidate t
Page 23 and 24: Introduction a) the soil compaction
Page 25 and 26: Experimental Methods 2.1.1.1 Test F
Page 27 and 28: Experimental Methods had been mount
Page 29 and 30: Experimental Methods track; the loa
Page 31 and 32: Experimental Methods 800/10.5/2.5 t
Page 33 and 34: Experimental Methods term. In the m
Page 35 and 36: Experimental Methods Soil Surface F
Page 37 and 38: Experimental Methods Depth (cm) 0 1
Page 39 and 40: Experimental Methods ence surface c
Page 41 and 42: Experimental Methods chine derives
Page 43 and 44: Experimental Methods depth. The dat
Page 45 and 46: Experimental Methods with water and
Page 47 and 48: Experimental Methods 2.4 Statistica
Page 49 and 50: Laboratory Studies Into Undercarria
Page 51 and 52: Laboratory Studies Into Undercarria
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Laboratory Studies Into Undercarria
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Field Study With Full Size Combine
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Alleviation of Soil Compaction Howe
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Alleviation of Soil Compaction not
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Alleviation of Soil Compaction in a
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Alleviation of Soil Compaction diff
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Soil Compaction Models sibilities t
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Soil Compaction Models depends on t
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Soil Compaction Models Wroth (1968)
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Soil Compaction Models however, the
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Soil Compaction Models level. Criti
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Soil Compaction Models Utilizing Ke
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Soil Compaction Models average of m
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Soil Compaction Models Depth (mm) -
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Soil Compaction Models ture content
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Soil Compaction Models with four ot
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Soil Compaction Models Predicted In
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Soil Compaction Models Depth (mm) -
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Soil Compaction Models and 13.7 % b
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Soil Compaction Models Rel. Density
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Soil Compaction Models VCL paramete
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Soil Compaction Models The approach
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Soil Compaction Models surface stay
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Soil Compaction Models This result
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Soil Compaction Models 6.6.1.3 Wate
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Soil Compaction Models σσ 1 (kPA)
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Soil Compaction Models pressure to
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Soil Compaction Models The response
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Soil Compaction Models On medium so
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Soil Compaction Models SOILFLEX tak
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Ancillary Experiments 7 ANCILLARY E
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Ancillary Experiments Average conta
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Ancillary Experiments In order to c
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Ancillary Experiments contrary, the
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Ancillary Experiments Figure 102: S
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Ancillary Experiments track and the
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Ancillary Experiments even when hav
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Ancillary Experiments 7.3.2 Influen
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Ancillary Experiments The results f
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Ancillary Experiments Figure 117: S
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Ancillary Experiments Contact Press
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Ancillary Experiments Figure 123: F
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Ancillary Experiments Sinkage (mm)
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Ancillary Experiments model which o
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Ancillary Experiments 7.3.5 The Inf
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Ancillary Experiments 7.3.7 Discuss
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Ancillary Experiments Terzaghi (194
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Ancillary Experiments contact area.
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Ancillary Experiments soil forward
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Conclusions � The longitudinal so
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Bibliography 10 BIBLIOGRAPHY Aboaba
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Bibliography Defossez, P., Richard,
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Bibliography Gregory, A.S.; Whalley
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Bibliography Lamande, M., Schjonnin
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Bibliography Seig, D., 1985. Soil C
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Appendix 11 APPENDIX Ph.D. Thesis D
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Appendix Figure 32: VCL sample at t
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Appendix comparison at the deepest
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Appendix Estimated Pressure (kPa) 2
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Appendix 11.1.1.2.1 SOCOMO One of t
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Appendix by Seig (1985) who showed
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Appendix Soil water content 15 % an
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Appendix Adapting critical state so
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Appendix density is obtained by add
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Appendix Table 5: Values of constan
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Appendix choice of a concentration
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Appendix 11.1.3.1 Dense/Hard and Lo
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Appendix 11.1.3.2 Stratified Soil C
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Appendix To summarize the ability t
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Appendix In the following the predi
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Appendix concentration factor of 4,
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Appendix 11.1.5.1 Confining Pressur
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Appendix Figure 24. The VCL created
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Appendix Rel. Density 2 1,9 1,8 1,7
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Appendix relation of � 1 to � 2
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Appendix Rel. Density 2 1,9 1,8 1,7
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Appendix Rel. Density 1,7 1,68 1,66
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Appendix Depth (mm) 0,0 100,0 200,0
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Appendix Figure 42: Plate in cookin
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Appendix � z � � �� k c p
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Appendix Table 8: n and k depending
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Appendix to the plate sinkage equat
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Appendix with a slight deviation fr
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Appendix Table 12: DBD values for a
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