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Ancillary Experiments gated. If it was possible to obtain vertical soil displacement data while implements were passing, probably more could be explained. Thus in a future study it is recommended to measure the pressure and actual displacement below a track simultaneously to trace vertical displacement at varying depths while a track passes. This would enable to investigate the effect of plate geometry in more detail as it was possible to replicate the true pressure distribution below the track, too. 7.3.6 Influence of LPPL on Predicted and Measured Increase in DBD The influence of LPPL on measured soil displacement was intensively shown. The remain- ing question is to which extend this was taken into consideration with existing soil compaction models. Therefore soil density increase predicted with COMPSOIL using the in- situ VCL developed in Section 6.3 was used to predict increase in DBD. The result was plotted against the corresponding LPPL in Figure 131. As it can be seen from the measured data on the left hand side compared to the predicted data on the right hand side, the overall tendency is very similar and both curves show similar curvature, too. The “outlier” in the measured term is obviously not represented in the predicted term. However, for the predicted diagram there is a similar increase in density increase for the low axle load as it was measured. The high axle load flattens, too. Soil Deformation (1/100 * % Increase in DBD) 0,18 0,16 0,14 0,12 0,10 0,08 0,06 High Axle Load Low Axle Load 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8 3,0 3,2 Load per PerimeterLength (t/m) Ph.D. Thesis Dirk Ansorge (2007) Predicted rel. Increase Increase in DBD 0,18 0,16 0,14 0,12 0,10 0,08 0,06 High Axle Load Low Axle Load 168 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8 3,0 3,2 Load per PerimeterLength (t/m) Figure 131: Measured (left) vs. predicted (right) increase in DBD against LPPL
Ancillary Experiments 7.3.7 Discussion, Conclusions, and further recommendations from LPPL It was shown that both contact area and load per perimeter length describe soil displacement. The importance of the LPPL having a significant influence can further be stressed by the mere vertical soil failure which will in detail be discussed in Section 7.5. Being able to describe the relative density increase in dependence of the reciprocal of the contact area, reciprocal of the perimeter, and the reciprocal of an interaction term between the two emphasized the overall validity of the concept as it was possible to predict the relative density increase for both full size and small scale experiments highly accurately. The benefit of a long narrow contact patch was shown by Seig (1985) and others. With this study it was possible to actually link a parameter to the plate shape. However, for actual tyre and track design the contact time has to be taken into consideration, too. The implica- tions of contact time on the geometry of the implement have yet to be investigated and it is recommended to measure the pressure and actual displacement below a track simultaneously to trace vertical displacement at varying depths while a track passes in a future study. This would answer the question to which extend it was sensible to take the effect of plate geometry into consideration with such experiments and whether it is necessary to replicate the true pressure distribution below the track, too, when considering contact time. For a future total evaluation and continuation of the work the availability of TexScan can contribute to the verification of the influence above as contact areas can be determined much more accurately and so can the perimeter length. 7.4 Influence of Pressure History on Sinkage There has been a long controversy between soil scientists and agricultural engineers about the influence of a peaked vs. a constant pressure history and their implication on resulting sinkage. In literature no information can be found concerning their effect. Thus it is not clear whether and if so to what extent sinkage is affected by the loading pattern. The availability of a triaxial test apparatus which allows the application of axial load pattern up to 1 Hz enabled this experiment on the influence of constant vs. peak pressure. The Ph.D. Thesis Dirk Ansorge (2007) 169
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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
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Experimental Methods 2.1.1.1 Test F
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Experimental Methods had been mount
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Experimental Methods track; the loa
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Experimental Methods 800/10.5/2.5 t
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Experimental Methods term. In the m
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Experimental Methods Soil Surface F
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Experimental Methods Depth (cm) 0 1
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Experimental Methods ence surface c
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Experimental Methods chine derives
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Experimental Methods depth. The dat
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Experimental Methods with water and
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Experimental Methods 2.4 Statistica
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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
Page 133 and 134: Soil Compaction Models Rel. Density
Page 135 and 136: Soil Compaction Models VCL paramete
Page 137 and 138: Soil Compaction Models The approach
Page 139 and 140: Soil Compaction Models surface stay
Page 141 and 142: Soil Compaction Models This result
Page 143 and 144: Soil Compaction Models 6.6.1.3 Wate
Page 145 and 146: Soil Compaction Models σσ 1 (kPA)
Page 147 and 148: Soil Compaction Models pressure to
Page 149 and 150: Soil Compaction Models The response
Page 151 and 152: Soil Compaction Models On medium so
Page 153 and 154: Soil Compaction Models SOILFLEX tak
Page 155 and 156: Ancillary Experiments 7 ANCILLARY E
Page 157 and 158: Ancillary Experiments Average conta
Page 159 and 160: Ancillary Experiments In order to c
Page 161 and 162: Ancillary Experiments contrary, the
Page 163 and 164: Ancillary Experiments Figure 102: S
Page 165 and 166: Ancillary Experiments track and the
Page 167 and 168: Ancillary Experiments even when hav
Page 169 and 170: Ancillary Experiments 7.3.2 Influen
Page 171 and 172: Ancillary Experiments The results f
Page 173 and 174: Ancillary Experiments Figure 117: S
Page 175 and 176: Ancillary Experiments Contact Press
Page 177 and 178: Ancillary Experiments Figure 123: F
Page 179 and 180: Ancillary Experiments Sinkage (mm)
Page 181 and 182: Ancillary Experiments model which o
Page 183: Ancillary Experiments 7.3.5 The Inf
Page 187 and 188: Ancillary Experiments Terzaghi (194
Page 189 and 190: Ancillary Experiments contact area.
Page 191 and 192: Ancillary Experiments soil forward
Page 193 and 194: Conclusions � The longitudinal so
Page 195 and 196: Bibliography 10 BIBLIOGRAPHY Aboaba
Page 197 and 198: Bibliography Defossez, P., Richard,
Page 199 and 200: Bibliography Gregory, A.S.; Whalley
Page 201 and 202: Bibliography Lamande, M., Schjonnin
Page 203 and 204: Bibliography Seig, D., 1985. Soil C
Page 205 and 206: Appendix 11 APPENDIX Ph.D. Thesis D
Page 207 and 208: Appendix Figure 32: VCL sample at t
Page 209 and 210: Appendix comparison at the deepest
Page 211 and 212: Appendix Estimated Pressure (kPa) 2
Page 213 and 214: Appendix 11.1.1.2.1 SOCOMO One of t
Page 215 and 216: Appendix by Seig (1985) who showed
Page 217 and 218: Appendix Soil water content 15 % an
Page 219 and 220: Appendix Adapting critical state so
Page 221 and 222: Appendix density is obtained by add
Page 223 and 224: Appendix Table 5: Values of constan
Page 225 and 226: Appendix choice of a concentration
Page 227 and 228: Appendix 11.1.3.1 Dense/Hard and Lo
Page 229 and 230: Appendix 11.1.3.2 Stratified Soil C
Page 231 and 232: Appendix To summarize the ability t
Page 233 and 234: 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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