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Laboratory Studies Into Undercarriage Systems Depth (mm) 0 100 200 300 400 500 600 700 Displacement (mm) -10 10 30 50 70 90 Figure 42: Soil displacement vs. depth for different track units 3.3.2.3 Longitudinal Pressure Profiles Stocks Westtrack Ph.D. Thesis Dirk Ansorge (2007) SPT TerraTrac 50bar LSD at 95% CI The pressure profiles for all treatments are shown in Figure 43. Absolute pressure varied from a minimum of 0.4 bar from one unit to a maximum of 1.8 bar of an other unit. Mainly the curves were distributed at 1.2 – 1.4 bar. The difference in time of pressure application was due to the individual length of each track unit. The Stocks unit showed the most uniform pressure application. The peak in the centre of the profile of the Westtrack unit indi- cated that its 3 mid-rollers were sitting lower than the front and the rear roller as the pressure was decreasing below the front and the rear roller compared to the centre. The Terra- Trac unit showed the typical Claas pressure profile with increasing pressure peaks from the front to the rear. On the contrary, the SPT unit had the highest peak below the centre of the unit and a strong decline in pressure to the rear roller. This was due to the load being ap- plied off-centre towards the front of the unit aiming for an equal pressure distribution un- der drawbar pull. Pressure data from an 800/10.5/2.5 run was included for reference show- ing the highest peak, but contact time was half of that of the track units. To statistically analyze the pressure-time histories the rectangularity was estimated. To do this each curve was divided by its maximum value resulting in a relative pressure ranging from 0 – 1. This data was averaged and the closer the average was to 1, the more rectangu- lar, and consequently uniform, the pressure profile was. Typical values were approximately 0.55. This is shown in Figure 44 whereby the 95% - CI bars are included. 54
Laboratory Studies Into Undercarriage Systems Pressure (bar) 3,0 2,8 2,6 2,4 2,2 2,0 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,5 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 Time (s) Terra Trac Westtrack Stocks SPT 800/10.5/2.5 Figure 43: Pressure profiles for track units including a 800/10.5/2.5 for reference The statistical analysis showed that the pressure application was only significantly different for the SPT unit with a rectangularity measure of 0.51 from the Stocks unit with a rectangularity measure of 0.61 (p-value 0.0067). The two remaining track units and the tyre show similar values of approximately 0.55. As the rectangularity of a tyre was within the range of tracks, it could not be used as a distinguishing characteristic. In Section 7.4 the significance of peak vs. average pressure in sinkage will be demonstrated and thus shows the importance of high rectangularity. Figure 45 shows the average contact pressure, maximum peak pressure and the average maxima and minima for the different units. The minima are always significantly smaller than the maxima except for the Westtrack which due to the triangular pressure profile has a more uniform pressure profile. Minima of all other units are similar, too. The average minima can be bigger than the average contact pressure as this calculation does not account for time. The peak pressures are always significantly higher than the average maxima except for the Stocks supporting a uniform pressure distribution seen already. Ph.D. Thesis Dirk Ansorge (2007) 55
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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
Page 19 and 20: Introduction � Ansorge, D. and Go
Page 21 and 22: Introduction 1.2 Aim To elucidate t
Page 23 and 24: Introduction a) the soil compaction
Page 25 and 26: Experimental Methods 2.1.1.1 Test F
Page 27 and 28: Experimental Methods had been mount
Page 29 and 30: Experimental Methods track; the loa
Page 31 and 32: Experimental Methods 800/10.5/2.5 t
Page 33 and 34: Experimental Methods term. In the m
Page 35 and 36: Experimental Methods Soil Surface F
Page 37 and 38: Experimental Methods Depth (cm) 0 1
Page 39 and 40: Experimental Methods ence surface c
Page 41 and 42: Experimental Methods chine derives
Page 43 and 44: Experimental Methods depth. The dat
Page 45 and 46: Experimental Methods with water and
Page 47 and 48: Experimental Methods 2.4 Statistica
Page 49 and 50: Laboratory Studies Into Undercarria
Page 69: Laboratory Studies Into Undercarria
Page 77 and 78: Field Study With Full Size Combine
Page 99 and 100: Alleviation of Soil Compaction Howe
Page 101 and 102: Alleviation of Soil Compaction not
Page 103 and 104: Alleviation of Soil Compaction in a
Page 105 and 106: Alleviation of Soil Compaction diff
Page 107 and 108: Soil Compaction Models sibilities t
Page 109 and 110: Soil Compaction Models depends on t
Page 111 and 112: Soil Compaction Models Wroth (1968)
Page 113 and 114: Soil Compaction Models however, the
Page 115 and 116: Soil Compaction Models level. Criti
Page 117 and 118: Soil Compaction Models Utilizing Ke
Page 119 and 120: 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
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Appendix 11 APPENDIX Ph.D. Thesis D
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Appendix Figure 32: VCL sample at t
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Appendix comparison at the deepest
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Appendix Estimated Pressure (kPa) 2
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Appendix 11.1.1.2.1 SOCOMO One of t
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Appendix by Seig (1985) who showed
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Appendix Soil water content 15 % an
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Appendix Adapting critical state so
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Appendix density is obtained by add
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Appendix Table 5: Values of constan
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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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