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Introduction The effect of wheel traffic on runoff and crop yield was investigated by Li et al. (2006), whereby they have found that controlled traffic seems to be the most beneficial solution for both high yields and reduced compaction. This agrees with results from Tullberg (2006). Little extra has been reported since Ansorge (2005, a) with respect to tracks. Excellent reviews of existing soil compaction models were compiled by Seig (1985) and Defossez and Richard (2002). The performance of two elastic and two elasto-plastic models was compared by Chi et al. (1993) in predicting stress and strain of a sandy loam soil and clay. Chi et al. (1993) point out that the assessment of soil parameters is mostly the largest source of error. Therefore a soil compaction model which can account for different soil conditions is of great value for machine designers and soil managers to evaluate the impact a machine pass can have under given soil conditions. Tyre and agricultural machin- ery manufacturers could evaluate tyre specification and axle configuration, respectively, at the design state. This thesis will describe a simple approach to obtain the slope and inter- cept parameters of a virgin compression line from contact pressure and soil density changes and use this with the model COMPSOIL (O’Sullivan et al., 1998) for a spectrum of soils. Following this approach, designers, advisers and farmers could assess the field impact of machines from a knowledge of the inflation pressure and the resulting rut depth. In contrast to the models SOCOMO (van den Akker, 2004) and TASC (Etiennen and Steinmann, 2002) COMPSOIL is actually able to quantify the soil density increase rather than simply stating a danger of soil compaction for given loads and inflation pressures. A detailed literature review on soil compaction models is given in Section 6.1. Overall a significant volume of work has been conducted in the area of soil compaction and as a result the soil physical principles of soil compaction appear to be clear, but its real implications with the soil conditions are less so. The results depend on the soil conditions and the author’s interpretation. With the exception of Ansorge (2005, a) laboratory studies were limited to loads smaller than 5 t and no published results have been found on the performance of tracks in laboratory conditions. This study aims to extend the laboratory inves- tigation from Ansorge (2005, a) into the effects of whole undercarriage systems with high axle loads on both wheels and tracks. Additionally the findings in the soil bin laboratory will be compared to a field experiment. Ph.D. Thesis Dirk Ansorge (2007) 4
Introduction 1.2 Aim To elucidate the mechanics of soil displacement causing compaction by combine harvester wheels/tyres and tracks at high axle loads on uniform soil conditions in controlled laboratory conditions and in field. 1.3 Objectives Objectives: 1. To investigate the effect of: a. multi - wheel systems as shown in Figure 1 b. the time of contact and the length of the contact patch c. the size and inflation pressure of a rear combine tyre following the passage of the front implement d. different track configurations on soil physical properties e. the load and inflation pressure of a light weight combine harvester on soil physical properties in controlled laboratory and field conditions. 2. To evaluate and develop existing soil compaction models to predict the effects of wheels/tyres and tracks on soil physical properties. 3. To determine the relative effects of wheels/tyres and tracks on the resulting tillage forces. Ph.D. Thesis Dirk Ansorge (2007) 5
Page 1 and 2: Cranfield University School of Appl
Page 3 and 4: Abstract Ancillary experiments show
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: Introduction � Ansorge, D. and Go
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
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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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