Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda

The purpose of this study was to model landslide occurrence (LO) in the hilly areas of Bududa District taking to consideration the effect of commonly known causative factors and an uncommon landslide causal factor of wind forces on slope with eucalyptus trees. Five different slope models, without an...

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Main Author:	Nelson, Okello
Format:	Thesis
Language:	English
Published:	2015
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/53918/25/OkelloNelsonMFKA2015.pdf
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id	my-utm-ep.53918
record_format	uketd_dc
spelling	my-utm-ep.539182020-10-08T03:25:20Z Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda 2015-01 Nelson, Okello TA Engineering (General). Civil engineering (General) The purpose of this study was to model landslide occurrence (LO) in the hilly areas of Bududa District taking to consideration the effect of commonly known causative factors and an uncommon landslide causal factor of wind forces on slope with eucalyptus trees. Five different slope models, without and with additional shear strength infrom of tree root cohesion have been use to obtain the final results of LO, with all subjected six (6) different failure criteria (FC). The first four failure criteria (FC1, FC2, FC3 and FC4) assumed were for; group of trees on the slope, tree at the top, tree in the middle and tree at the toe of the slope , while FC5 and FC6 were for slope models with rainfall infiltration only and rainfall plus group of tree weight respectively. Beaufort wind scale 11 was used, and Tree Diameters at Breast Heights (DBH) were varied, commencing with 25cm, 30cm and 60cm for assumed eucalyptus tree height of 25cm. The additional shear strength due to an increased cohesion from the roots ( was assumed, on the top soil layer of silty clay. Finite element analysis with SEEP/W 2007 was coupled with Limit equilibrium analysis software of SLOPE/W 2007 to achieve expected output or results from different failure criteria. Initial suction of 50kPa at the top of silty clay and 20kPa in the layer of silty gravel, with a total 1044 generated deformed mesh boundary condition were used in transient seepage analysis. Slope model 1 with eucalyptus trees of DBH 25cm yielded an output minimum factor of safety (FOS) of 1.012 for FC3 and value of 1.253 for FC3 (an increase of 23.81% from slope model 4), without and with increased cohesion respectively. With DBH increased to a maximum of 60cm, for slope model 3, safety of the community around this site diminished as the FoS reduced to 0.562 with FC2 and 0.601 with FC3 on day 25, without cohesion, just hours before the fateful day on the 26th June 2012 and remained below 1.0 (from 0.601 to 0.800) with FC3 with roots cohesion, although a gain in the FoS of 33.11% was realized. 2015-01 Thesis http://eprints.utm.my/id/eprint/53918/ http://eprints.utm.my/id/eprint/53918/25/OkelloNelsonMFKA2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:85685 masters 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) Nelson, Okello Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda
description	The purpose of this study was to model landslide occurrence (LO) in the hilly areas of Bududa District taking to consideration the effect of commonly known causative factors and an uncommon landslide causal factor of wind forces on slope with eucalyptus trees. Five different slope models, without and with additional shear strength infrom of tree root cohesion have been use to obtain the final results of LO, with all subjected six (6) different failure criteria (FC). The first four failure criteria (FC1, FC2, FC3 and FC4) assumed were for; group of trees on the slope, tree at the top, tree in the middle and tree at the toe of the slope , while FC5 and FC6 were for slope models with rainfall infiltration only and rainfall plus group of tree weight respectively. Beaufort wind scale 11 was used, and Tree Diameters at Breast Heights (DBH) were varied, commencing with 25cm, 30cm and 60cm for assumed eucalyptus tree height of 25cm. The additional shear strength due to an increased cohesion from the roots ( was assumed, on the top soil layer of silty clay. Finite element analysis with SEEP/W 2007 was coupled with Limit equilibrium analysis software of SLOPE/W 2007 to achieve expected output or results from different failure criteria. Initial suction of 50kPa at the top of silty clay and 20kPa in the layer of silty gravel, with a total 1044 generated deformed mesh boundary condition were used in transient seepage analysis. Slope model 1 with eucalyptus trees of DBH 25cm yielded an output minimum factor of safety (FOS) of 1.012 for FC3 and value of 1.253 for FC3 (an increase of 23.81% from slope model 4), without and with increased cohesion respectively. With DBH increased to a maximum of 60cm, for slope model 3, safety of the community around this site diminished as the FoS reduced to 0.562 with FC2 and 0.601 with FC3 on day 25, without cohesion, just hours before the fateful day on the 26th June 2012 and remained below 1.0 (from 0.601 to 0.800) with FC3 with roots cohesion, although a gain in the FoS of 33.11% was realized.
format	Thesis
qualification_level	Master's degree
author	Nelson, Okello
author_facet	Nelson, Okello
author_sort	Nelson, Okello
title	Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda
title_short	Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda
title_full	Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda
title_fullStr	Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda
title_full_unstemmed	Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda
title_sort	modeling of landslide occurrence in the hilly areas of bududa district, eastern uganda
granting_institution	Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department	Faculty of Civil Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/53918/25/OkelloNelsonMFKA2015.pdf
_version_	1747817657404489728

Modeling of landslide occurrence in the hilly areas of Bududa District, Eastern Uganda

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