Modelling of stress transfer in root-reinforced soils informed by four-dimensional X-ray computed tomography and digital volume correlation data

Daniel Bull, Joel Smethurst, Gerrit Meijer, I. Sinclair, Fabrice Pierron, T. Roose, William Powrie, Glyn Bengough

Research output: Contribution to journalArticlepeer-review

1 Citation (SciVal)

Abstract

Vegetation enhances soil shearing resistance through water uptake and root reinforcement. Analytical models for soils reinforced with roots rely on input parameters that are difficult to measure, leading to widely varying predictions of behaviour. The opaque heterogeneous nature of rooted soils results in complex soil–root interaction mechanisms that cannot easily be quantified. The authors measured, for the first time, the shear resistance and deformations of fallow, willow-rooted and gorse-rooted soils during direct shear using X-ray computed tomography and digital volume correlation. Both species caused an increase in shear zone thickness, both initially and as shear progressed. Shear zone thickness peaked at up to 35 mm, often close to the thickest roots and towards the centre of the column. Root extension during shear was 10–30% less than the tri-linear root profile assumed in a Waldron-type model, owing to root curvature. Root analogues used to explore the root–soil interface behaviour suggested that root lateral branches play an important role in anchoring the roots. The Waldron-type model was modified to incorporate non-uniform shear zone thickness and growth, and accurately predicted the observed, up to sevenfold, increase in shear resistance of root-reinforced soil.
Original languageEnglish
Article number20210210
JournalProceedings of the Royal Society A
Volume478
Issue number2257
Early online date5 Jan 2022
DOIs
Publication statusPublished - 31 Jan 2022

Keywords

  • Direct shear
  • X-ray computed tomography
  • digital volume correlation
  • root reinforcement
  • shear zone thickness
  • slope stability

ASJC Scopus subject areas

  • Mathematics(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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