Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour

Gerrit Meijer (Lead / Corresponding author), Anthony Bengough, Jonathan Knappett, Kenneth Loades, Bruce Nicoll

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The spatial distribution of plant roots is an important parameter when the stability of vegetated slopes is to be assessed. Previous studies in both laboratory and field conditions have shown that a penetrometer adapted with a blade-shaped tip can be used to detect roots from sudden drops in penetrometer resistance. Such drops can be related to root properties including diameter, stiffness and strength using simple Winkler foundation models, thereby providing a field instrument for rapid quantification of root properties and distribution. While this approach has proved useful for measuring single widely-spaced roots, it has not previously been determined how the penetrometer response changes as a result of roots being in close proximity. Therefore in this study 1-g physical modelling (at 1:1 scale) was conducted to study the effect of vertical root spacing using horizontal, straight 3D-printed root analogues. Results show that when roots are closely spaced, there is significant interaction between them, resulting in higher apparent root displacements to failure and an increased amount of energy being dissipated. This preliminary work shows that the interpretive models used to analyse the penetrometer trace require further development to account for root-soil-root interactions in densely rooted soil.
Original languageEnglish
Title of host publicationPhysical Modelling in Geotechnics
Subtitle of host publicationProceedings of the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), July 17-20, 2018, London, United Kingdom
EditorsAndrew McNamara, Sam Divall, Richard Goodey
PublisherTaylor & Francis
Pages425-430
Number of pages6
Volume1
ISBN (Print)ISBN 978-1-138-34419-8
Publication statusPublished - Jul 2018
Event9th International Conference on Physical Modelling in Geoetchnics - City University, London, United Kingdom
Duration: 17 Jul 201820 Jul 2018

Conference

Conference9th International Conference on Physical Modelling in Geoetchnics
CountryUnited Kingdom
CityLondon
Period17/07/1820/07/18

Fingerprint

behavioral resistance
penetrometers
spatial distribution
soil
energy

Cite this

Meijer, G., Bengough, A., Knappett, J., Loades, K., & Nicoll, B. (2018). Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour. In A. McNamara, S. Divall, & R. Goodey (Eds.), Physical Modelling in Geotechnics: Proceedings of the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), July 17-20, 2018, London, United Kingdom (Vol. 1, pp. 425-430). Taylor & Francis.
Meijer, Gerrit ; Bengough, Anthony ; Knappett, Jonathan ; Loades, Kenneth ; Nicoll, Bruce. / Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour. Physical Modelling in Geotechnics: Proceedings of the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), July 17-20, 2018, London, United Kingdom. editor / Andrew McNamara ; Sam Divall ; Richard Goodey. Vol. 1 Taylor & Francis, 2018. pp. 425-430
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title = "Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour",
abstract = "The spatial distribution of plant roots is an important parameter when the stability of vegetated slopes is to be assessed. Previous studies in both laboratory and field conditions have shown that a penetrometer adapted with a blade-shaped tip can be used to detect roots from sudden drops in penetrometer resistance. Such drops can be related to root properties including diameter, stiffness and strength using simple Winkler foundation models, thereby providing a field instrument for rapid quantification of root properties and distribution. While this approach has proved useful for measuring single widely-spaced roots, it has not previously been determined how the penetrometer response changes as a result of roots being in close proximity. Therefore in this study 1-g physical modelling (at 1:1 scale) was conducted to study the effect of vertical root spacing using horizontal, straight 3D-printed root analogues. Results show that when roots are closely spaced, there is significant interaction between them, resulting in higher apparent root displacements to failure and an increased amount of energy being dissipated. This preliminary work shows that the interpretive models used to analyse the penetrometer trace require further development to account for root-soil-root interactions in densely rooted soil.",
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Meijer, G, Bengough, A, Knappett, J, Loades, K & Nicoll, B 2018, Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour. in A McNamara, S Divall & R Goodey (eds), Physical Modelling in Geotechnics: Proceedings of the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), July 17-20, 2018, London, United Kingdom. vol. 1, Taylor & Francis, pp. 425-430, 9th International Conference on Physical Modelling in Geoetchnics, London, United Kingdom, 17/07/18.

Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour. / Meijer, Gerrit (Lead / Corresponding author); Bengough, Anthony; Knappett, Jonathan; Loades, Kenneth; Nicoll, Bruce.

Physical Modelling in Geotechnics: Proceedings of the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), July 17-20, 2018, London, United Kingdom. ed. / Andrew McNamara; Sam Divall; Richard Goodey. Vol. 1 Taylor & Francis, 2018. p. 425-430.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - The spatial distribution of plant roots is an important parameter when the stability of vegetated slopes is to be assessed. Previous studies in both laboratory and field conditions have shown that a penetrometer adapted with a blade-shaped tip can be used to detect roots from sudden drops in penetrometer resistance. Such drops can be related to root properties including diameter, stiffness and strength using simple Winkler foundation models, thereby providing a field instrument for rapid quantification of root properties and distribution. While this approach has proved useful for measuring single widely-spaced roots, it has not previously been determined how the penetrometer response changes as a result of roots being in close proximity. Therefore in this study 1-g physical modelling (at 1:1 scale) was conducted to study the effect of vertical root spacing using horizontal, straight 3D-printed root analogues. Results show that when roots are closely spaced, there is significant interaction between them, resulting in higher apparent root displacements to failure and an increased amount of energy being dissipated. This preliminary work shows that the interpretive models used to analyse the penetrometer trace require further development to account for root-soil-root interactions in densely rooted soil.

AB - The spatial distribution of plant roots is an important parameter when the stability of vegetated slopes is to be assessed. Previous studies in both laboratory and field conditions have shown that a penetrometer adapted with a blade-shaped tip can be used to detect roots from sudden drops in penetrometer resistance. Such drops can be related to root properties including diameter, stiffness and strength using simple Winkler foundation models, thereby providing a field instrument for rapid quantification of root properties and distribution. While this approach has proved useful for measuring single widely-spaced roots, it has not previously been determined how the penetrometer response changes as a result of roots being in close proximity. Therefore in this study 1-g physical modelling (at 1:1 scale) was conducted to study the effect of vertical root spacing using horizontal, straight 3D-printed root analogues. Results show that when roots are closely spaced, there is significant interaction between them, resulting in higher apparent root displacements to failure and an increased amount of energy being dissipated. This preliminary work shows that the interpretive models used to analyse the penetrometer trace require further development to account for root-soil-root interactions in densely rooted soil.

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Meijer G, Bengough A, Knappett J, Loades K, Nicoll B. Laboratory investigation into the effect of model root spacing on the blade penetrometer depth-resistance behaviour. In McNamara A, Divall S, Goodey R, editors, Physical Modelling in Geotechnics: Proceedings of the 9th International Conference on Physical Modelling in Geotechnics (ICPMG 2018), July 17-20, 2018, London, United Kingdom. Vol. 1. Taylor & Francis. 2018. p. 425-430