Cranfield University

List of Figures and Tables
List of Figures
Figure 1: Alternative multi - wheel configurations ........................................................ 6
Figure 2: Initial penetrometer resistance profile from the soil bin................................. 8
Figure 3: Single Wheel/Track test apparatus with a track (left) and a tyre (right)......... 9
Figure 4: The combine harvesters taken into the field ................................................. 11
Figure 5: Sandy loam field layout, with shallow tilled and subsoiled parts................. 12
Figure 6: Clay field layout............................................................................................ 12
Figure 7: Vertical cut through soil with points of talcum powder .............................. 14
Figure 8: Vector diagram of soil movement after the pass of an 800/10.5/2.5 tyre..... 15
Figure 9: Soil displacement vs. depth after a pass of an 800/10.5/2.5 ......................... 16
Figure 10: Differently colored sand method to determine soil displacement ................ 18
Figure 11: Fishing hook method .................................................................................... 19
Figure 12: Movement of talcum powder and fishhooks in the soil bin ......................... 19
Figure 13: Fishing hook distribution in the sandy loam subsoiled................................. 21
Figure 14: Fishing hook distribution in the sandy loam shallow tilled .......................... 21
Figure 15: Fishing hook distribution in the clay ............................................................ 22
Figure 16: Excavation of the fishing hooks.................................................................... 22
Figure 17: Penetrometer resistance across the soil bin for the 900/10.5/1.9 tyre........... 23
Figure 18: The Troxler on a field plot............................................................................ 25
Figure 19: Placement of Troxler, fishhook and reference surface in test area............... 26
Figure 20: Complete triaxial cell apparatus ................................................................... 28
Figure 21: Average pressure and peak pressure............................................................. 30
Figure 22: Repeated treatments with near identical initials and results ......................... 33
Figure 23: Penetrometer resistance at three speeds and a multi pass of the 900/5/0.5... 34
Figure 24: Soil displacement vs. depth for different speeds for the 900/5/0.5............... 34
Figure 25: Average increase in DBD vs. speed.............................................................. 35
Figure 26: Penetrometer resistance for the rear tyres..................................................... 39
Figure 27: Penetrometer resistance with and without influence of rear tyre.................. 39
Figure 28: Penetrometer resistance for different undercarriage systems ....................... 40
Figure 29: Group of track type penetrometer resistance including 680-680.................. 40
Figure 30: Group of wheel type penetrometer resistance............................................... 40
Figure 31: Soil displacement vs. depth for the rear tyres............................................... 42
Figure 32: Soil displacement caused by the front and rear implement tyre ................... 43
Ph.D. Thesis Dirk Ansorge (2007)
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