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Ancillary Experiments Contact Pressure / Density Increase 1300 1200 1100 1000 900 800 700 1,8 2,0 2,2 2,4 2,6 2,8 3,0 3,2 3,4 3,6 3,8 Form Factor* Diagonal D Lineares Fitten von Data1_D Figure 122: Contact pressure / density increase vs. form factor * diagonal Hence, this approach is not able to reduce or better explain the observed sinkage behavior satisfactorily. 7.3.4 Derivation of Load per perimeter length (LPPL) As the best method for describing plate sinkage in dependence of plate shape did not lead to satisfying results for the full size tyre/track data, the idea emerged that the circumference of the contact area might play an important role because of the punching failure of the soil caused by the tyres and tracks; the concept of load per perimeter length was created (LPPL). As visualized in Figure 123, the concept of the LPPL is a shear zone of limited thickness at the perimeter supporting the enclosed soil when load is applied. The effect is proportional to the perimeter length. The data of the LPPL is plotted against measured increase in soil density Figure 124. In general soil density increase increases with an increase in LPPL, similar to the contact pressure in Figure 108, however, the spread of the data is much less with a R 2 0.858 of and a p-value of 0.0007. The fact that the LPPL is smaller for the smaller loads leads to a closer relationship between the high and the low axle load groups. Interesting to note is that all the data shows marginal noise if the 800/10.5/1.25 (the square at approximately 2.4 t/m, 0.115) is disregarded causing a much smaller increase in soil density increase than ex- pected due to its LPPL. Ph.D. Thesis Dirk Ansorge (2007) 160
Ancillary Experiments Figure 123: Footprint of a tyre with corresponding perimeter and shear area The theory of Söhne (1954) can thus be confirmed by taking the influence of load on stress into account. If the soil has to carry a weight, which exceeds its own bearing capacity, the enclosed soil will support itself on the surrounding soil due to cohesion. The smaller the contact area, the larger in relation is this shear area and consequently the bigger is the effect of the LPPL. For a circular plate the circumference in proportion to the area enclosed decreases most efficiently with an increasing area. This is due to the fact that a circle sur- rounds the biggest area with the smallest circumference possible. The LPPL accounts for this and is highest for a circular plate. Consequently a long rectangular footprint maxi- mizees the outside area load. This agrees with the benefit of the tracks as they cause the same soil displacement as the rear tyres because they have similar contact pressures and a similar LPPL. Soil Deformation (1/100 * % Increase in DBD) 0,18 0,16 0,14 0,12 0,10 0,08 0,06 0,04 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) High Axle Load Low Axle Load Linear Fit Figure 124: Soil deformation vs. LPPL for tyre and track treatments Ph.D. Thesis Dirk Ansorge (2007) 161
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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
Page 125 and 126: Soil Compaction Models with four ot
Page 127 and 128: Soil Compaction Models Predicted In
Page 129 and 130: 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: Ancillary Experiments Contact Press
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 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
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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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