Modelling of stress transfer in root-reinforced soils informed by four-dimensional X-ray computed tomography and digital volume correlation data
Modelling of stress transfer in root-reinforced soils informed by four-dimensional X-ray computed tomography and digital volume correlation data
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 seven-fold, increase in shear resistance of root-reinforced soil.
Direct shear, Slope stability, Root reinforcement, Digital volume correlation, X-ray computed tomography, Shear zone thickness
Bull, Daniel
3569ba02-89de-4398-a14d-02c3f9b4eab2
Smethurst, Joel
8f30880b-af07-4cc5-a0fe-a73f3dc30ab5
Meijer, Gerrit
7b9009ee-fc42-434b-82ab-827cf7959e79
Sinclair, Ian
6005f6c1-f478-434e-a52d-d310c18ade0d
Pierron, Fabrice
a1fb4a70-6f34-4625-bc23-fcb6996b79b4
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Powrie, William
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
Bengough, Glyn
916e33a7-985b-4b01-a76c-acdfcdd15fdb
5 January 2022
Bull, Daniel
3569ba02-89de-4398-a14d-02c3f9b4eab2
Smethurst, Joel
8f30880b-af07-4cc5-a0fe-a73f3dc30ab5
Meijer, Gerrit
7b9009ee-fc42-434b-82ab-827cf7959e79
Sinclair, Ian
6005f6c1-f478-434e-a52d-d310c18ade0d
Pierron, Fabrice
a1fb4a70-6f34-4625-bc23-fcb6996b79b4
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Powrie, William
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
Bengough, Glyn
916e33a7-985b-4b01-a76c-acdfcdd15fdb
Bull, Daniel, Smethurst, Joel, Meijer, Gerrit, Sinclair, Ian, Pierron, Fabrice, Roose, Tiina, Powrie, William and Bengough, Glyn
(2022)
Modelling of stress transfer in root-reinforced soils informed by four-dimensional X-ray computed tomography and digital volume correlation data.
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 478 (2257), [RSPA-2021-0210].
(doi:10.1098/rspa.2021.0210).
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 seven-fold, increase in shear resistance of root-reinforced soil.
Text
Bull et al 2021 Revised manuscript v5 FINAL
- Accepted Manuscript
More information
Accepted/In Press date: 30 November 2021
Published date: 5 January 2022
Keywords:
Direct shear, Slope stability, Root reinforcement, Digital volume correlation, X-ray computed tomography, Shear zone thickness
Identifiers
Local EPrints ID: 452832
URI: http://eprints.soton.ac.uk/id/eprint/452832
ISSN: 1364-5021
PURE UUID: 6d462724-9aa1-4e71-8500-4a43e9693839
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Date deposited: 21 Dec 2021 17:51
Last modified: 09 Jan 2022 03:33
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Contributors
Author:
Gerrit Meijer
Author:
Glyn Bengough
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