Modelling tree stability in unsaturated soils

Tree stability holds a paramount concern in Singapore where millions of trees were planted around the country. Numerous research works have been done on tree stability but mainly focus on the tree trunk and the tree root architecture. In this study, the focus was on unsaturated soil mechanics. Conve...

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Main Author: Low, Laurence
Other Authors: Harianto Rahardjo
Format: Final Year Project
Language:English
Published: 2018
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Online Access:http://hdl.handle.net/10356/74748
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-747482023-03-03T17:01:31Z Modelling tree stability in unsaturated soils Low, Laurence Harianto Rahardjo School of Civil and Environmental Engineering DRNTU::Engineering::Civil engineering Tree stability holds a paramount concern in Singapore where millions of trees were planted around the country. Numerous research works have been done on tree stability but mainly focus on the tree trunk and the tree root architecture. In this study, the focus was on unsaturated soil mechanics. Conventionally, numerical modelling in unsaturated soil was done in two-dimensional analyses due to the limitation of the software. However, tree is a three-dimensional object, using two-dimensional tree model to conduct the simulation may not be accurate. Therefore, three-dimensional tree model using ANSYS is necessary to analyse tree stability in unsaturated soil. SEEP/W and SIGMA/W were used to validate the two-dimensional ANSYS model for steady-state seepage analyse and deformation analyses respectively. Site instrumentation data was then compared with the result obtained by the three-dimensional and two-dimensional ANSYS model. The result showed that the three-dimensional model indeed provided more accurate result compared with the two-dimensional model. Coupled analyses and parametric study were carried out using ANSYS three-dimensional model to study the rainfall effect on tree stability. The result showed that when rainfall intensity reached to. 1.00×10−6 m/s , the force to cause tree failure decreased significantly. Some improvements can be made in future study such as stiffness of soil can be taken into consideration during rainfall as infiltration might change stiffness of soil and cause tree failure. Bachelor of Engineering (Civil) 2018-05-23T08:11:40Z 2018-05-23T08:11:40Z 2018 Final Year Project (FYP) http://hdl.handle.net/10356/74748 en Nanyang Technological University 47 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Civil engineering
spellingShingle DRNTU::Engineering::Civil engineering
Low, Laurence
Modelling tree stability in unsaturated soils
description Tree stability holds a paramount concern in Singapore where millions of trees were planted around the country. Numerous research works have been done on tree stability but mainly focus on the tree trunk and the tree root architecture. In this study, the focus was on unsaturated soil mechanics. Conventionally, numerical modelling in unsaturated soil was done in two-dimensional analyses due to the limitation of the software. However, tree is a three-dimensional object, using two-dimensional tree model to conduct the simulation may not be accurate. Therefore, three-dimensional tree model using ANSYS is necessary to analyse tree stability in unsaturated soil. SEEP/W and SIGMA/W were used to validate the two-dimensional ANSYS model for steady-state seepage analyse and deformation analyses respectively. Site instrumentation data was then compared with the result obtained by the three-dimensional and two-dimensional ANSYS model. The result showed that the three-dimensional model indeed provided more accurate result compared with the two-dimensional model. Coupled analyses and parametric study were carried out using ANSYS three-dimensional model to study the rainfall effect on tree stability. The result showed that when rainfall intensity reached to. 1.00×10−6 m/s , the force to cause tree failure decreased significantly. Some improvements can be made in future study such as stiffness of soil can be taken into consideration during rainfall as infiltration might change stiffness of soil and cause tree failure.
author2 Harianto Rahardjo
author_facet Harianto Rahardjo
Low, Laurence
format Final Year Project
author Low, Laurence
author_sort Low, Laurence
title Modelling tree stability in unsaturated soils
title_short Modelling tree stability in unsaturated soils
title_full Modelling tree stability in unsaturated soils
title_fullStr Modelling tree stability in unsaturated soils
title_full_unstemmed Modelling tree stability in unsaturated soils
title_sort modelling tree stability in unsaturated soils
publishDate 2018
url http://hdl.handle.net/10356/74748
_version_ 1759853709463912448