Soil strength changes in trials using two tyre options on haulout trucks

This study measured changes in soil cone resistance as an indicator of soil compaction after the passage of haulout trucks running dual tyres or super single tyres. Measurements were made to a depth of 600 mm in the interspace and in transects from the middle of one row to the middle of the adjacent row. Traffic consisted of one, two, three and four passes by both dual tyres and super single tyres and one and two passes of reduced pressure versus standard pressure super single tyres. Soil cone resistance increased with an increasing number of passes under the dual tyres. There was, however, only a small increase in soil resistance under the super single tyres. There was less change in soil cone resistance after the passage of the super single tyres compared with the dual tyres. There was a small reduction in soil cone resistance when low tyre pressure was used compared with high tyre pressure in the super single tyres. Soil COne resistance in the row was greater after the passage of the dual tyres compared with lowpressure super single tyres. There is an apparent advantage in using super single tyres on haul out trucks compared with the conventional dual tyres to minimise changes in soil physical properties.