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Ancillary Experiments The results in general agree with Koolen and Vaandrager (1984) who did not detect lateral soil movement at a relationship of � �� 0. 5 which is close to the relationship assumed 3 1 for minor and major principal stresses in Section 6.3.2 for a concentration factor of five and equal to the relationship at a concentration factor of four. In an investigation of Gibson (1967) the surface did not settle outside the loaded area. Chancellor and Schmidt (1962) report a circular pattern of soil movement whereby with increasing rut depth the soil is pushed more sideways, but none or only small amounts are pushed above the original surface. Nevertheless Chancellor and Schmidt (1962) state as well, that a high percentage of volume reduction was caused by vertical displacement and suggest to measure rut depth to measure soil displacement supporting the procedure described to gain the increase in DBD in Section 6.3. In their case contact pressures were higher and thus they observed sideways soil movement. Issensee (2007) reported the same finding from horizontal penetrometer resistance measurements whereby no increase in resistance could be detected outside the loaded area. All this agrees with the findings of Kirby et al. (1997) who detected the largest vertical shear displacement underneath the tyre edge and ties back to the effect of the LPPL derived in Section 7.3. Hence it has been possible to clearly explain the nature of the vertical soil failure with two independent soil mechanics theories, plate sinkage and passiv earth pressure theory, re- spectively. Therefore it can be concluded that if the pressure bulbs of Söhne (1953) reach outside the loaded area, they at least do not to influence the direction of soil movement. Results from Lamade et al. (2006) suggest that these pressure bulbs do not reach outside the contact area. 7.6 Conclusions on Ancillary Experiements � The benefit of the tracks could be attributed to the dense layer created at the soil surface and their small contact pressure. This layer is caused by an alternating backward forward soil movement below a track. Overall backward soil movement was more pronounced below a track whereby the surface 150 mm of soil tilted significantly backwards (-4 mm). In comparison to this the passage of a tyre tilted the Ph.D. Thesis Dirk Ansorge (2007) 174
Ancillary Experiments soil forward (+2 mm) which was not significantly different from zero. In both cases this is limited to the top 150 mm in weak soil conditions. � The influence of lugs on variation in soil displacement could statistically be proven to a depth of 100 mm. At 200 mm depth and below the influence of lugs could not be statistically verified. � Load per perimeter length describes measured increase in DBD more accurately than contact pressure for full size tyres. Overall relative soil density increase can accurately be described by the reciprocal of contact area, perimeter, and an interac- tion term for both full size and small scale sinkage results. The validity is empha- sized by an insignificant intercept making the prediction zero when it should be zero. � The time history of pressure application has an important influence on sinkage. A pressure peak lead to 1/3 more sinkage than constant pressure. � The punching soil failure observed by this study and others can be explained by plate sinkage theory and passive earth pressure theory. Ph.D. Thesis Dirk Ansorge (2007) 175
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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
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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
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 and 184: Ancillary Experiments 7.3.5 The Inf
Page 185 and 186: Ancillary Experiments 7.3.7 Discuss
Page 187 and 188: Ancillary Experiments Terzaghi (194
Page 189: Ancillary Experiments contact area.
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
Page 235 and 236: Appendix concentration factor of 4,
Page 237 and 238: Appendix 11.1.5.1 Confining Pressur
Page 239 and 240: 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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