An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization

The stability of slopes is a major concern in the field of geotechnical engineering. Two-dimensional (2D) limit equilibrium methods are usually implemented in this field due to their simplicity. However, these methods ignore the features of the third dimension of slopes. Although three-dimensional (...

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Main Author:	Kalatehjari, Roohollah
Format:	Thesis
Language:	English
Published:	2013
Subjects:	TA Engineering (General) Civil engineering (General) TH Building construction
Online Access:	http://eprints.utm.my/id/eprint/33764/5/RoohollahKalatehjariPFKA2013.pdf
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spelling	my-utm-ep.337642017-07-23T07:22:58Z An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization 2013-02 Kalatehjari, Roohollah TA Engineering (General). Civil engineering (General) TH Building construction The stability of slopes is a major concern in the field of geotechnical engineering. Two-dimensional (2D) limit equilibrium methods are usually implemented in this field due to their simplicity. However, these methods ignore the features of the third dimension of slopes. Although three-dimensional (3D) methods tried to remove the previous limitation, most of them assumed the direction of sliding, simplified or ignored the intercolumn forces, and avoided to search for location and shape of three-dimensional critical slip surface. This study was performed to overcome the mentioned limitations. In the present study, a new slope stability method was established based on the force and moment equilibrium in two vertical directions that was able to find the unique direction of sliding. Moreover, a modified Particle Swarm Optimization was developed by replacing the worst particle of each swarm with the previous global best particle and using a dynamic inertia weight to determine the 3D critical slip surface. Then, a computer program was established to model 3D slopes and perform the required calculations. Several benchmark problems were re-analyzed to verify the results of the study and good agreements were achieved with the results of previous studies when different failure mechanisms as ellipsoid, cylindrical, and composite slip surfaces were successfully applied in the analysis. The results indicated that the 3D factor of safety of a slope is always greater than its corresponding 2D factor. Moreover, the end effect in 3D analysis was found to be more significance in the problems with lower ratio of length to the width of the sliding mass. It was also found that the presence of water and weak layer enlarged this effect. Through the verification study, it was observed that different sliding directions produce different factors of safety, while the lowest value of factor of safety and 3D critical slip surface is only reachable through the real direction of sliding. Finally, case studies of actual stability problems were analyzed to find their critical slip surfaces. Achieving the minimum factor of safety of 0.977 for the critical slip surface of a failed slope demonstrated the validity of performance of presented computer code. Based on the obtained results, this study successfully overcame the mentioned limitations of the previous methods. The results of this study provided a better understanding of the actual failure mechanism and helped to enhance the safety and reduced the economic and health costs due to slope failure by a more detailed analysis than before. 2013-02 Thesis http://eprints.utm.my/id/eprint/33764/ http://eprints.utm.my/id/eprint/33764/5/RoohollahKalatehjariPFKA2013.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:69804?site_name=Restricted Repository 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) TH Building construction
spellingShingle	TA Engineering (General) Civil engineering (General) TH Building construction Kalatehjari, Roohollah An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
description	The stability of slopes is a major concern in the field of geotechnical engineering. Two-dimensional (2D) limit equilibrium methods are usually implemented in this field due to their simplicity. However, these methods ignore the features of the third dimension of slopes. Although three-dimensional (3D) methods tried to remove the previous limitation, most of them assumed the direction of sliding, simplified or ignored the intercolumn forces, and avoided to search for location and shape of three-dimensional critical slip surface. This study was performed to overcome the mentioned limitations. In the present study, a new slope stability method was established based on the force and moment equilibrium in two vertical directions that was able to find the unique direction of sliding. Moreover, a modified Particle Swarm Optimization was developed by replacing the worst particle of each swarm with the previous global best particle and using a dynamic inertia weight to determine the 3D critical slip surface. Then, a computer program was established to model 3D slopes and perform the required calculations. Several benchmark problems were re-analyzed to verify the results of the study and good agreements were achieved with the results of previous studies when different failure mechanisms as ellipsoid, cylindrical, and composite slip surfaces were successfully applied in the analysis. The results indicated that the 3D factor of safety of a slope is always greater than its corresponding 2D factor. Moreover, the end effect in 3D analysis was found to be more significance in the problems with lower ratio of length to the width of the sliding mass. It was also found that the presence of water and weak layer enlarged this effect. Through the verification study, it was observed that different sliding directions produce different factors of safety, while the lowest value of factor of safety and 3D critical slip surface is only reachable through the real direction of sliding. Finally, case studies of actual stability problems were analyzed to find their critical slip surfaces. Achieving the minimum factor of safety of 0.977 for the critical slip surface of a failed slope demonstrated the validity of performance of presented computer code. Based on the obtained results, this study successfully overcame the mentioned limitations of the previous methods. The results of this study provided a better understanding of the actual failure mechanism and helped to enhance the safety and reduced the economic and health costs due to slope failure by a more detailed analysis than before.
format	Thesis
qualification_level	Master's degree
author	Kalatehjari, Roohollah
author_facet	Kalatehjari, Roohollah
author_sort	Kalatehjari, Roohollah
title	An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
title_short	An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
title_full	An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
title_fullStr	An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
title_full_unstemmed	An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
title_sort	improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization
granting_institution	Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department	Faculty of Civil Engineering
publishDate	2013
url	http://eprints.utm.my/id/eprint/33764/5/RoohollahKalatehjariPFKA2013.pdf
_version_	1747816179395723264

An improvised three-dimensional slope stability analysis based on limit equilibrium method by using particle swarm optimization

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