Tree water uptake on suction distribution in unsaturated tropical residual soil slope

This study provides an investigation of active root tree zone located at the toe of a slope. This section and its vicinity generated matric suction due to tree water uptake on tropical residual soil slope. The research employed several approaches i.e field monitoring, laboratory experimental and num...

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Main Author:	Ishak, Mohd. Fakhrurrazi
Format:	Thesis
Language:	English
Published:	2014
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/77738/1/MohdFakhrurraziIshakPFKA2014.pdf
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id	my-utm-ep.77738
record_format	uketd_dc
spelling	my-utm-ep.777382018-07-04T11:42:46Z Tree water uptake on suction distribution in unsaturated tropical residual soil slope 2014-10 Ishak, Mohd. Fakhrurrazi TA Engineering (General). Civil engineering (General) This study provides an investigation of active root tree zone located at the toe of a slope. This section and its vicinity generated matric suction due to tree water uptake on tropical residual soil slope. The research employed several approaches i.e field monitoring, laboratory experimental and numerical modelling. A field monitoring was carried out to collect matric suction data at the slope with two conditions; in absence of a tree and with a tree located at the toe of a slope. The unsaturated shear strength behaviour of soil under different stress level is investigated, using uncomplicated testing procedure subject to actual matric suction encountered during field monitoring. The numerical simulation modelling was applied based on the laboratory results to obtain the most appropriate condition to replicate the tree water uptake within the soil slope. A decrease in matric suction occured after a long duration of intense rainfall. This condition was function as an initial condition before the water uptake driven by active root tree generated to the maximum matric suction (low moisture content). The pattern of matric suction profiles revealed that majority of matric suction changes was greater at the proximity of tree trunk below 4 m and at a shallow depth of 0.5 m. Transpiration on single mature tree has significantly altered the matric suction or moisture variation distribution on an unsaturated soil slope. This study also illustrated the nonlinear relationship between the apparent shear strength and suction influencing the stability of the slope. The assessment of slope stability due to the influence of a tree induced suction was provided in this research. The factor of safety against slope failure has improved up to 63 % on slope with tree at toe compared to a slope without tree. Lastly, the numerical simulation modelling of matric suction induced by a tree has been verified through comparison to actual field monitoring results recorded during the dry period. Generally, an acceptable aggrement between simulation and field monitoring results has been achieved. This research delivers a strong belief that a preserved mature tree can improve soil properties in slopes designs. 2014-10 Thesis http://eprints.utm.my/id/eprint/77738/ http://eprints.utm.my/id/eprint/77738/1/MohdFakhrurraziIshakPFKA2014.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:98537 phd doctoral Universiti Teknologi Malaysia, Faculty of Civil Engineering Faculty of Civil Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TA Engineering (General) Civil engineering (General)
spellingShingle	TA Engineering (General) Civil engineering (General) Ishak, Mohd. Fakhrurrazi Tree water uptake on suction distribution in unsaturated tropical residual soil slope
description	This study provides an investigation of active root tree zone located at the toe of a slope. This section and its vicinity generated matric suction due to tree water uptake on tropical residual soil slope. The research employed several approaches i.e field monitoring, laboratory experimental and numerical modelling. A field monitoring was carried out to collect matric suction data at the slope with two conditions; in absence of a tree and with a tree located at the toe of a slope. The unsaturated shear strength behaviour of soil under different stress level is investigated, using uncomplicated testing procedure subject to actual matric suction encountered during field monitoring. The numerical simulation modelling was applied based on the laboratory results to obtain the most appropriate condition to replicate the tree water uptake within the soil slope. A decrease in matric suction occured after a long duration of intense rainfall. This condition was function as an initial condition before the water uptake driven by active root tree generated to the maximum matric suction (low moisture content). The pattern of matric suction profiles revealed that majority of matric suction changes was greater at the proximity of tree trunk below 4 m and at a shallow depth of 0.5 m. Transpiration on single mature tree has significantly altered the matric suction or moisture variation distribution on an unsaturated soil slope. This study also illustrated the nonlinear relationship between the apparent shear strength and suction influencing the stability of the slope. The assessment of slope stability due to the influence of a tree induced suction was provided in this research. The factor of safety against slope failure has improved up to 63 % on slope with tree at toe compared to a slope without tree. Lastly, the numerical simulation modelling of matric suction induced by a tree has been verified through comparison to actual field monitoring results recorded during the dry period. Generally, an acceptable aggrement between simulation and field monitoring results has been achieved. This research delivers a strong belief that a preserved mature tree can improve soil properties in slopes designs.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Ishak, Mohd. Fakhrurrazi
author_facet	Ishak, Mohd. Fakhrurrazi
author_sort	Ishak, Mohd. Fakhrurrazi
title	Tree water uptake on suction distribution in unsaturated tropical residual soil slope
title_short	Tree water uptake on suction distribution in unsaturated tropical residual soil slope
title_full	Tree water uptake on suction distribution in unsaturated tropical residual soil slope
title_fullStr	Tree water uptake on suction distribution in unsaturated tropical residual soil slope
title_full_unstemmed	Tree water uptake on suction distribution in unsaturated tropical residual soil slope
title_sort	tree water uptake on suction distribution in unsaturated tropical residual soil slope
granting_institution	Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department	Faculty of Civil Engineering
publishDate	2014
url	http://eprints.utm.my/id/eprint/77738/1/MohdFakhrurraziIshakPFKA2014.pdf
_version_	1747817818856882176

Tree water uptake on suction distribution in unsaturated tropical residual soil slope

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