Abstract

Compressive properties of arable and forest soils are typically derived from data obtained in uniaxial confined compression tests. However, the stress field, final state of compression and thus compressive properties derived from such tests are dependent on sample dimensions, soil-cylinder wall friction and soil material properties. In this study, we analysed the stress field and bulk density distribution within a cylindrical soil sample under uniaxial compression, and how these are affected by sample dimension, soil-cylinder wall friction and elastic properties of soil. For this, we modelled a uniaxial compression test using the finite element method (FEM) and performed simulations for a range of sample diameter to height ratios (D/h), different values of soil-wall friction coefficient (mu) and different soil elastic properties (Young's modulus and Poisson's ratio). We use experimental data to validate the findings. The results showed a high impact of soil-cylinder wall friction on the stress field within the sample. This resulted in stress concentration at the top of sample edges (walls) and decreasing stresses at the bottom of the sample. However, the relative impact of soil-wall friction on sample average behaviour decreased with increasing D/h. These results suggest that the effect of soil-wall friction on sample-average bulk density cannot be neglected unless D/h > 8. Correction of bulk density for mu and D/h could be a practical way to compare data obtained in laboratories using different sample sizes.

Keywords

Compressive properties; Coefficient of friction; Confined soil compression test; Poisson's ratio; Finite element model

Published in

Soil and Tillage Research
2019, Volume: 189, pages: 15-24
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Keller, Thomas

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • Agroscope

UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.1016/j.still.2018.12.021

Permanent link to this page (URI)

https://res.slu.se/id/publ/99223