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Laboratory Studies Into Undercarriage Systems caused similar soil displacement as a traditionally wheeled machine, but with a smaller soil displacement at depth. � Only if wheel load was maintained below 5 t for large section width / diameter tyres, no residual soil displacement between 500 – 600 mm depth was apparent as it was for track type units. � The possible variation in belt tension of a friction driven track unit (TerraTrac) between 50 and 200 bar affects the resulting soil displacement and pressure distribu- tion below the track insignificantly. � An evaluation of different track types resulted in the fact that there is an optimum amount of rollers. Additional rollers have only a slight impact, but less rollers can increase soil displacement significantly. Belt tension for sprocket driven track units should be kept in mind as too low a pressure can increase soil displacement, too. All standard track units achieved similar results, a prototype unit created significantly more soil displacement due to the reduced number of rollers. � The soil displacement caused by implement tyres (4.5 t) usually fitted to the rear axle of a combine was within the range of a rubber track at 12 t. � A larger section height can compensate for a smaller section width as shown by Ansorge (2005, a), too. � Passes at low speed on the headlands can cause the same soil displacement as three passes of the same tyre at operation speeds. Ph.D. Thesis Dirk Ansorge (2007) 60
Field Study With Full Size Combine Harvesters 4 FIELD STUDY WITH FULL SIZE COMBINE HARVESTERS In spring 2006 a field study was conducted aiming to verify soil bin results on a sandy loam and clay soils with full size combine harvesters. For the detailed field set up, refer to Section 2.1.2. A description of parameter measurement can be found in Section 2.2 for penetrometer resistance, rut depth and DBD which were measured similar to the soil bin. Soil displacement was measured using fishing hooks and a gamma ray probe was used as well to measure DBD as detailed in Sections 2.2.1.2 and 2.2.3.2, respectively. The scatter of the measurements in the field results is much larger than in the soil bin laboratory, with high probability due to the inhomogeneities, e.g. variations in water content, soil texture and structure, etc. in the field soil. 4.1 Results of the field experiment 4.1.1 Soil Displacement Due to the pattern of the observed soil displacement data from the fishhook experiments shown exemplarily for the clay soil in Figure 48, different regression functions were evalu- ated, quadratic, 1/x, logarithmic, and root functions, respectively, all including a linear term. Attempting to describe the data of all three soils with quadratic and 1/x functions including a linear term reduced mainly to linear functions. Fitting logarithmic and root functions, the linear terms disappeared in the majority of cases, but the differences of the R 2 for the linear, the logarithmic, and the square root functions are marginal with less than 2 % for the clay and the subsoiled sandy loam. The R 2 is greater than 0.7 for the wheeled configurations and exceeds 0.45 for the tracked treatments. As Figure 48 shows the linear term is appropriate because it has zero displacement at a depth where the majority of data from this depth and below is zero. This confirms the findings discussed in 2.2.1.1 assuming to approximate soil displacement by a linear function. On the shallow tilled sandy loam plot, no coherent picture was gained. For the track data all models reduced to a linear regression function with R 2 greater than 0.7. But for the wheeled treatments, the full model (linear plus quadratic) fitted best with R 2 greater than 0.75. However, as full models had never been chosen before, and the particular data distri- Ph.D. Thesis Dirk Ansorge (2007) 61
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Cranfield University School of Appl
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Abstract Ancillary experiments show
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Table of Contents TABLE OF CONTENTS
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Table of Contents 4.1.3 Analysis of
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Table of Contents 11.1.1.1 Comparis
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List of Figures and Tables Figure 3
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List of Figures and Tables Figure 1
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Nomenclature NOMENCLATURE Abbreviat
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Introduction 1 INTRODUCTION 1.1 Bac
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Introduction � Ansorge, D. and Go
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Introduction 1.2 Aim To elucidate t
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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 75: Laboratory Studies Into Undercarria
Page 79 and 80: Field Study With Full Size Combine
Page 99 and 100: Alleviation of Soil Compaction Howe
Page 101 and 102: Alleviation of Soil Compaction not
Page 103 and 104: Alleviation of Soil Compaction in a
Page 105 and 106: Alleviation of Soil Compaction diff
Page 107 and 108: Soil Compaction Models sibilities t
Page 109 and 110: Soil Compaction Models depends on t
Page 111 and 112: Soil Compaction Models Wroth (1968)
Page 113 and 114: Soil Compaction Models however, the
Page 115 and 116: Soil Compaction Models level. Criti
Page 117 and 118: Soil Compaction Models Utilizing Ke
Page 119 and 120: Soil Compaction Models average of m
Page 121 and 122: Soil Compaction Models Depth (mm) -
Page 123 and 124: Soil Compaction Models ture content
Page 125 and 126: 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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