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Appendix estimation of VCL parameters and Bekker-parameters. Section 6.7 showed a mathematical justification of this from Sime and Upadhyaya (2004). The advantage of the Bekker approach is, that its parameters can be measured much easier than traditional critical state soil mechanics parameters, however, still needs plate sinkage tests performed to gain the parameters. Therefore the assessment is not as straight forward as the one proposed in Section 6.3 whereby the measurements can be taken from rut depths created by tyres. Figure 47 shows that the predicted rut depths from COMPSOIL are intermediate between the Bekker approach utilizing the contact width and the one using half the contact length. Predicted Rut Depth (mm) 500 450 400 350 300 250 200 150 100 50 0 0 50 100 150 200 250 300 350 Measured Rut Depth (mm) Real Contact Width Half Contact Length COMPSOIL 1:1 Line Linear (1:1 Line) Figure 47: Predicted vs. Measured depth of the tyres from plate sinkage data and from COMPSOIL An adjustment for plate sizes was not conducted due to the insufficient result on the soft soil conditions. For a more detailed approach and in order to reduce the errors further a sinkage study would need to be undertaken using different plate sizes to estimate kc and kphi properly. According to McKyes and Fan (1985) at least 3-4 plate sizes have to be used to reduce the coefficient of variation to 27 % and 16 %, respectively. 11.1.7.3.2 Sinkage of Tracks The track sinkage equation could possibly be utilized to explain the different behaviour of different tracks. However, it has not been used for a proper evaluation of the sinkage, as it assumes n to be equal to 1 which is only the case on very soft soils. Nevertheless Table 9 includes predictions of track sinkage gained from the plate sinkage approach of Eq. 4 whereby only k*b has been considered, the track equation Eq. 8 (which for a slag of 0 reduces Ph.D. Thesis Dirk Ansorge (2007) 239
Appendix to the plate sinkage equation of Eq. 4 with an n-factor of 1). Additionally the following Bernstein equation is included, too: 6* W z � 5* r * b * k * D Eq. 9 whereby r is the number of rollers in the track unit and D is equal to the diameter of the largest roller of the track unit. Table 9: Measured and predicted track sinkages using different approaches Unit / Belt Slag Plate (Eq. 4) (mm) Track (Eq. 8) (mm) Bernstein (Eq. 9) (mm) Measured Sinkage (mm) Stocks/0.05 0.2 80 51 55 Stocks/0.02 No Slag 64 No Slag PTS/0.05 0.2 102 58 85 PTS/0.02 No Slag 79 No Slag Westtrack/0.05 0.1 70 36 55 Westtrack/0.02 No Slag 57 No Slag TerraTrac/0.05 0.15 77 29 55 TerraTrac/0.02 No Slag 62 No Slag According to Table 9 the general plate sinkage equation would predict sinkages too small. The track equation assuming a slag of 0.02 estimates sinkage too high in a range of 2 – 9 mm depending on the unit except for PTS whereby sinkage would be underestimated. This is sensible as it is the unit with the least belt tension. Consequently a track slag of 0.05 results in a sinkage prediction even larger and less appropriate except possibly for the PTS. The Bernstein equation significantly underestimates sinkage except for the Stocks. Thus in general the track equation (Eq. 8) predicts sinkage most accurately. Unfortunately true track slag has not been measured during the experiments and therefore no further calibration/adjustment can be made. Ph.D. Thesis Dirk Ansorge (2007) 240
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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
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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
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
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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
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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
Page 241 and 242: Appendix Rel. Density 2 1,9 1,8 1,7
Page 243 and 244: Appendix relation of � 1 to � 2
Page 245 and 246: Appendix Rel. Density 2 1,9 1,8 1,7
Page 247 and 248: Appendix Rel. Density 1,7 1,68 1,66
Page 249 and 250: Appendix Depth (mm) 0,0 100,0 200,0
Page 251 and 252: Appendix Figure 42: Plate in cookin
Page 253 and 254: Appendix � z � � �� k c p
Page 255: Appendix Table 8: n and k depending
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Page 261: Appendix Table 12: DBD values for a
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