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Ancillary Experiments Hence, a full model with reciprocal parameters explained the variation in the data best. To confirm this, the approach was utilized for the plate sinkage data from the triaxial test cell, too. Hereby the perimeter parameter drops out first, followed by the area. In the end the model remains with the interaction term being the only parameter significantly describing the variation in the data. Again, the intercept is insignificant except for the model with the interaction term only. This small scale data follows the same pattern which could be adopted for the soil bin data, too. If the parameter having the least influence would need to drop out independent of its significance, it was the perimeter. In the following reduced model, the area would drop out and as with the small scale data the interaction term re- mained. Hence, the same behavior pattern could be shown for both the soil bin and the triaxial data. This supports the significance of the interaction term and perimeter length in addition to contact area. Looking at the individual terms shows an agreement in absolute values between the regres- sion lines for the full size and scaled experiments.The general equation describing soil density increase is as follows: a b Rel. densityIncrease � � � Perimeter Area c Perimeter * Area Eq. 11 As the intercept for both full size and scaled models was not significant it was not added to the equation. The reciprocal of the area is the only negative term in the equation. This shows the contribution of the area to a reduction of the density increase is greatest for small size plates. The contribution of the perimeter to an increase in density decreases with increasing perimeter. The reciprocal of the interaction term adds to the density increase, too, in a decreasing manner as contact size and perimeter length increase. For the particular data a = 0.0013, b = 0.0003, and c = 0.0005. It was a success to be able to describe the behavior of small scale plates with the same method as tyres although the plates only apply static pressure and do not simulate the kneading of a tyre. It can be concluded that the same link is connecting small scale plate sinkage experiments to real tyre pass data as for the in-situ VCL dapproach. Ph.D. Thesis Dirk Ansorge (2007) 166
Ancillary Experiments 7.3.5 The Influence of Contact Time Due to the different lengths of the plates, contact time varies when assuming the same ve- hicle speed for traveling. All the scaled plate sinkage experiments before do not take different contact times of the implements into consideration. Therefore a further experiment was conducted using the square plate, an intermediate rectangular plate (which had not been used before) and the long rectangular plate representing a “track”. All plates had the same area and the same average load (0.236 kN) was applied. The contact time for the square plate was maintained, the contact time for the intermediate and track shape plate were adapted representing their increased contact length and assuming constant speed in a hypothetical pass. Therefore contact time for the track was 3.6 s and for the intermediate plate 2.4 s compared to 1.8 s which was previously used and is now only used for the square plate having the shortest length. The circular plate was not considered as its diame- ter is similar to the length of the square. As the following diagram shows, the track creates the most sinkage due to its prolonged contact time. There is no difference between the intermediate and the square plate. Sinkage (mm) 20 15 10 5 0 Track Intermediate Square Shape Figure 130: Sinkage for different plate shapes accounting for different contact times including 95% - CI These results show the complexity in designing undercarriage systems. All results have to be taken into consideration simultaneously, because if only contact shape is taken into consideration one conclusion might be drawn, however, when taking contact time into ac- count, the result might be different. These results contradict the real results from the soil bin whereby tracks caused a smaller sinkage than tyres although having a longer contact time. However, the overall reduced contact pressure is not taken into consideration in this study. Moreover, the track specific soil density increase is described in Section 6.4 for the track specific in-situ VCL and in Section 7.1 the longitudinal soil movement is investi- Ph.D. Thesis Dirk Ansorge (2007) 167
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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) -
Page 131 and 132: 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: Ancillary Experiments model which o
Page 185 and 186: Ancillary Experiments 7.3.7 Discuss
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
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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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