Grass evapotranspiration-induced suction in slope

case study

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2 Citations (Scopus)
92 Downloads (Pure)

Abstract

Grass evapotranspiration (ET) has been recognised to potentially affect shallow slope stability due to additional soil suction induced by root–water uptake. Some limited field studies showed higher suction induced in vegetated soil than that in bare soil, but some reported the opposite. In order to improve the understanding of the hydrological role of grass ET, this study explores suction responses of grassed slopes based on the current knowledge of soil–water–root interaction on root–water uptake in unsaturated soil. Three case histories, which included measurements of suction in both bare and grassed slopes, are selected for new interpretation. It is revealed that during drying, ET-induced suction in grassed slope was not necessarily higher than that by evaporation in bare slope. When grass ET took place in relatively wet soil that has insufficient soil aeration (i.e. suction lower than that corresponding to anaerobiosis point; 5–12 kPa for sandy soil), induced suction in grassed slope could be 20% lower. During rainfall, the presence of grass appears to help in retaining higher suction in slope composed of silty clay, as compared with bare slope. On the contrary, for sandy soil, no discernible difference of suction retained between grassed and bare slopes is observed.
Original languageEnglish
Pages (from-to)155-165
Number of pages11
JournalProceedings of the Institution of Civil Engineers: Environmental Geotechnics
Volume3
Issue number3
Early online date11 Sep 2015
DOIs
Publication statusPublished - Jun 2016

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Evapotranspiration
suction
evapotranspiration
grass
Soils
soil
sandy soil
anaerobiosis
Slope stability
silty clay
bare soil
slope stability
Rain
Drying
Clay
aeration
Evaporation
evaporation
rainfall

Keywords

  • Geotechnical engineering
  • Field testing & monitoring
  • Environment

Cite this

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title = "Grass evapotranspiration-induced suction in slope: case study",
abstract = "Grass evapotranspiration (ET) has been recognised to potentially affect shallow slope stability due to additional soil suction induced by root–water uptake. Some limited field studies showed higher suction induced in vegetated soil than that in bare soil, but some reported the opposite. In order to improve the understanding of the hydrological role of grass ET, this study explores suction responses of grassed slopes based on the current knowledge of soil–water–root interaction on root–water uptake in unsaturated soil. Three case histories, which included measurements of suction in both bare and grassed slopes, are selected for new interpretation. It is revealed that during drying, ET-induced suction in grassed slope was not necessarily higher than that by evaporation in bare slope. When grass ET took place in relatively wet soil that has insufficient soil aeration (i.e. suction lower than that corresponding to anaerobiosis point; 5–12 kPa for sandy soil), induced suction in grassed slope could be 20{\%} lower. During rainfall, the presence of grass appears to help in retaining higher suction in slope composed of silty clay, as compared with bare slope. On the contrary, for sandy soil, no discernible difference of suction retained between grassed and bare slopes is observed.",
keywords = "Geotechnical engineering, Field testing & monitoring, Environment",
author = "Leung, {Anthony Kwan}",
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language = "English",
volume = "3",
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journal = "Proceedings of the Institution of Civil Engineers: Environmental Geotechnics",
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TY - JOUR

T1 - Grass evapotranspiration-induced suction in slope

T2 - case study

AU - Leung, Anthony Kwan

PY - 2016/6

Y1 - 2016/6

N2 - Grass evapotranspiration (ET) has been recognised to potentially affect shallow slope stability due to additional soil suction induced by root–water uptake. Some limited field studies showed higher suction induced in vegetated soil than that in bare soil, but some reported the opposite. In order to improve the understanding of the hydrological role of grass ET, this study explores suction responses of grassed slopes based on the current knowledge of soil–water–root interaction on root–water uptake in unsaturated soil. Three case histories, which included measurements of suction in both bare and grassed slopes, are selected for new interpretation. It is revealed that during drying, ET-induced suction in grassed slope was not necessarily higher than that by evaporation in bare slope. When grass ET took place in relatively wet soil that has insufficient soil aeration (i.e. suction lower than that corresponding to anaerobiosis point; 5–12 kPa for sandy soil), induced suction in grassed slope could be 20% lower. During rainfall, the presence of grass appears to help in retaining higher suction in slope composed of silty clay, as compared with bare slope. On the contrary, for sandy soil, no discernible difference of suction retained between grassed and bare slopes is observed.

AB - Grass evapotranspiration (ET) has been recognised to potentially affect shallow slope stability due to additional soil suction induced by root–water uptake. Some limited field studies showed higher suction induced in vegetated soil than that in bare soil, but some reported the opposite. In order to improve the understanding of the hydrological role of grass ET, this study explores suction responses of grassed slopes based on the current knowledge of soil–water–root interaction on root–water uptake in unsaturated soil. Three case histories, which included measurements of suction in both bare and grassed slopes, are selected for new interpretation. It is revealed that during drying, ET-induced suction in grassed slope was not necessarily higher than that by evaporation in bare slope. When grass ET took place in relatively wet soil that has insufficient soil aeration (i.e. suction lower than that corresponding to anaerobiosis point; 5–12 kPa for sandy soil), induced suction in grassed slope could be 20% lower. During rainfall, the presence of grass appears to help in retaining higher suction in slope composed of silty clay, as compared with bare slope. On the contrary, for sandy soil, no discernible difference of suction retained between grassed and bare slopes is observed.

KW - Geotechnical engineering

KW - Field testing & monitoring

KW - Environment

U2 - 10.1680/envgeo.14.00010

DO - 10.1680/envgeo.14.00010

M3 - Article

VL - 3

SP - 155

EP - 165

JO - Proceedings of the Institution of Civil Engineers: Environmental Geotechnics

JF - Proceedings of the Institution of Civil Engineers: Environmental Geotechnics

SN - 2051-803X

IS - 3

ER -