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The influence of tree root water uptake on the long term hydrology of a clay fill railway embankment

The influence of tree root water uptake on the long term hydrology of a clay fill railway embankment
The influence of tree root water uptake on the long term hydrology of a clay fill railway embankment
This paper uses a numerical model to investigate the influence of tree root water uptake and tree removal on pore water pressures and the vertical movement of a clay fill railway embankment. Simulated results of soil wetting and drying are compared with field measurements from an instrumented railway embankment before and after tree removal. A parametric study compares the influence of vegetation on the seasonal movement of the embankment slope. The simulations and field measurements show that while trees cause significant seasonal variations in pore water pressure and water content near the soil surface, they can maintain persistent soil suctions at depth within the tree rooting zone. Demonstration of this result using a numerical model requires a root water uptake function that separates spatially the processes of water infiltration, evaporation and transpiration. When all of the trees are removed, the persistent soil suctions established by the trees are lost as water infiltrates from the soil surface. Leaving the trees in place over the bottom third of the slope can maintain persistent suctions at the slope toe, while potentially also reducing seasonal ground movements at the crest that may adversely affect railway track geometry.
2214-3912
31-48
Briggs, K.
8974f7ce-2757-4481-9dbc-07510b416de4
Smethurst, J. A.
8f30880b-af07-4cc5-a0fe-a73f3dc30ab5
Powrie, W.
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
O'Brien, A.S.
d88d5bd9-31ba-41e4-86f5-c4a6e2536f39
Briggs, K.
8974f7ce-2757-4481-9dbc-07510b416de4
Smethurst, J. A.
8f30880b-af07-4cc5-a0fe-a73f3dc30ab5
Powrie, W.
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
O'Brien, A.S.
d88d5bd9-31ba-41e4-86f5-c4a6e2536f39

Briggs, K., Smethurst, J. A., Powrie, W. and O'Brien, A.S. (2016) The influence of tree root water uptake on the long term hydrology of a clay fill railway embankment. Transportation Geotechnics, 9, 31-48. (doi:10.1016/j.trgeo.2016.06.001).

Record type: Article

Abstract

This paper uses a numerical model to investigate the influence of tree root water uptake and tree removal on pore water pressures and the vertical movement of a clay fill railway embankment. Simulated results of soil wetting and drying are compared with field measurements from an instrumented railway embankment before and after tree removal. A parametric study compares the influence of vegetation on the seasonal movement of the embankment slope. The simulations and field measurements show that while trees cause significant seasonal variations in pore water pressure and water content near the soil surface, they can maintain persistent soil suctions at depth within the tree rooting zone. Demonstration of this result using a numerical model requires a root water uptake function that separates spatially the processes of water infiltration, evaporation and transpiration. When all of the trees are removed, the persistent soil suctions established by the trees are lost as water infiltrates from the soil surface. Leaving the trees in place over the bottom third of the slope can maintain persistent suctions at the slope toe, while potentially also reducing seasonal ground movements at the crest that may adversely affect railway track geometry.

Text
__soton.ac.uk_ude_PersonalFiles_Users_jas_mydocuments_Embankment project_Magnolia Road models PAPER_FINAL submitted draft - for e-prints_Hawkwell Paper_Modelling 8June2016.pdf - Accepted Manuscript
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More information

Submitted date: 16 May 2016
Accepted/In Press date: 14 June 2016
e-pub ahead of print date: 22 June 2016
Published date: 1 December 2016
Organisations: Infrastructure Group

Identifiers

Local EPrints ID: 396417
URI: https://eprints.soton.ac.uk/id/eprint/396417
ISSN: 2214-3912
PURE UUID: f3115248-fd5d-4bfb-8667-df5739ea38db
ORCID for W. Powrie: ORCID iD orcid.org/0000-0002-2271-0826

Catalogue record

Date deposited: 09 Jun 2016 08:43
Last modified: 16 Jul 2019 01:09

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