Effects of tire inflation pressure and field traffic on compaction of a sandy clay soil as measured by cone index and permeability.

Abstract

Chehaibi, S., M. Khelifi, A. Boujelban, K. Abrougui. 2012. Effects of tire inflation pressure and field traffic on compaction of a sandy clay soil as measured by cone index and permeability. Canadian Biosystems Engineering/Le genie des biosystemes au Canada 54: 2.92.15. Many external factors have an effect on soil compaction, including the contact pressure generated at the soil-tire interface and the inflation pressure of tires. The main objective of this study was to investigate the effects of number of wheeled tractor passes and tire inflation pressures on the compaction and permeability of a sandy clay soil. Tests of soil compaction were conducted at the Higher Institute of Agronomy of Chott-Mariem, Sousse, Tunisia. Soil cone indices and permeability were measured under different number of tractor passes (one, two, and three) and tire inflation pressure (50 kPa, 100 kPa, and 150 kPa). A tractor of 59 kW with a total mass of 2,910 kg (1,715 kg on the rear axle) was used for the tests. Results showed that repeated passes increased soil compaction essentially in the upper horizons. This compaction, as measured by cone index, was positively correlated with tire inflation pressure. Indeed, the compaction was less pronounced under low tire inflation pressure. However, soil cone index remains closely related to soil moisture content. Multiple tractor passes also significantly reduce the soil permeability (P < 0.05). Similarly, our results showed that the permeability was significantly affected by tire inflation pressure and considerably decrease when increasing the selected pressure (50, 100, and 150 kPa). However, the correct tire inflation pressure indicated by the manufacturer varies from 84 to 140 kPa.