Figure 2 - uploaded by Mohammad Reza Mosaddeghi
Content may be subject to copyright.
Iso-strength (cone index) contours on vertical plane before (left) and after (right) conducting the plate sinkage test to a maximum stress of 600 kPa on the topsoil at water content and bulk density of 16 %w/w and 1.42 Mg m-3 , respectively.
Source publication
Plate sinkage test (PST) is an in situ method for measuring soil compaction and behavior under agricultural vehicles. One of the disadvantages of this method is that the measured properties (e.g. pre-compaction stress and modulus of stiffness) could not be easily related to a specific soil layer. The objective of this study was to investigate the p...
Contexts in source publication
Context 1
... and water content on soil behavior under PST. Soil layering/anisotropy could be due to soil forming processes and/or anthropogenic activities like tillage and compaction. At high soil water content, the stress-affected zone and soil vertical and lateral deformations were extended beyond the plate due to lubrication effect of water on soil flow (Fig. 2). At a lower soil water content, the iso-strength contours before the test showed that the strength of the subsoil was high at places which the test was ran (Fig. 3). Therefore, topsoil under the plate during the test was mainly deformed laterally into the surrounding loose soil. The strength variation in soil profile which could be ...
Context 2
... low water content, the soil compaction was mainly occurred vertically and a high strength (CI) zone appeared immediately beneath the plate (Fig. 4). Although the strength of the topsoil was high due to low water content but also because of low initial subsoil strength in this case (Fig. 4), the soil sinkage was comparable with its value at higher water contents (Figs. 2 and 3). Comparing Figures 2, 3 and 4 demonstrated the effect of soil water content and changes of soil strength in the soil profile on stress distribution and soil deformation under the loading plate. ...
Context 3
... the strength of the topsoil was high due to low water content but also because of low initial subsoil strength in this case (Fig. 4), the soil sinkage was comparable with its value at higher water contents (Figs. 2 and 3). Comparing Figures 2, 3 and 4 demonstrated the effect of soil water content and changes of soil strength in the soil profile on stress distribution and soil deformation under the loading plate. ...
Context 4
... so that the lateral movement and extension of soil compaction to deeper layers were limited. It could be said that the compaction process at low water content was similar to confined compression test (CCT). However, the lower strength of the soil and lubricating effect of water at high water content would extend soil compaction to deeper layers (Fig. 2). Therefore, maximum compaction might be occurred at deeper (confined) layers in such conditions. At the depth of 25 cm, an abrupt increase in CI was observed which was caused by a plow pan together with argillic horizon. The existence of argillic horizon in the soil was also reported by Lakzian ...
Citations
... The damage on the top surface layers of the soil is assumed to be high when the slip in the drive tires exceeds 15% (Battiato et al., 2015), and this reduces productivity and increases fuel consumption (Battiato and Diserens, 2017), which can be well observed at low vertical load on the tire (6 kN). Increasing soil moisture content also has some impacts on increasing the amount of slip in the treatments with similar condition of vertical load and inflation pressure, this is because the loading capacity and the value of vertical and lateral soil deformation, and generally the relative resistance of the soil layers mainly depend on the moisture content (Mosaddeghi et al., 2004). The mean error of tire slip using FEM model for moisture contents of 11.20% d.b., 14.86% d.b., and 18.68% d.b. were 11.44%, 12.42% and 6.29%, respectively. ...
In the present study, the effect of vertical load, tire inflation pressure and soil moisture content on power loss in tire under controlled soil bin conditions were investigated. Also a finite element model of tire-soil interaction in order to achieve a suitable model for predicting power loss in tire was created. Increasing the vertical load on the tire had a noteworthy impact on increasing the tire contact volume with the soil, reducing the percentage of slip, and increasing the rolling resistance; although, reducing the load on the tire had the opposite effect. At a constant inflation pressure, by increasing the vertical load on the tire, the amount of power loss due to the rolling resistance, and the total power loss in the tire increased. Increase in soil moisture content increased the power loss caused by slip. Increasing the inflation pressure at a constant vertical load, also increasing the soil moisture content, led to an increase in the power loss caused by rolling resistance, and increase total power loss. The obtained error for estimating power loss of rolling resistance and total power loss was satisfactory and confirmed the acceptability of the model for power loss estimation.
The rolling resistance and rutting incurred by towed flotation implement tyres were investigated on an arable clay soil in three different soil strength conditions. Three radial (600/55R26.5) and two bias ply (600/55–26.5) tyres were compared. Experimental wheel loads were in the 35.4–36.4 kN range. Tyre inflation pressures, representing typical field operation, and road transport applications were in 100–150 kPa and 150–200 kPa, respectively. Soil strength was determined from mean soil penetration resistance (CI0–15, in the layer 0–15 cm) and mean cohesion (C0–10, 0–10 cm). Wheel rolling resistance evaluated by the coefficient of rolling resistance (CRR), rut depth (RD), driving speed, and field gradient were measured with the tyres mounted on a test trailer hitched to a tractor. CI0–15 and C0–10 values predicted the sinkage and the resistance to travel motion on clay soil reasonably well. When the CI0–15 was less than 1 MPa and C0–10 was below 100 kPa, CRR and RD increased rapidly. On average, CRR was 20% lower for the radials than the bias plies. In soft conditions (CI0–15 ⩽ 0.48 MPa), the radials produced 15% shallower ruts than bias plies, and the CRR was lower and RD shallower with field inflation pressures than with road pressures used. According to our results, flotation tyres can be recommended to agricultural machines when the implement or trailer is used in soft soil conditions.
