Forepoling pre-support application in the shallow tunneling through weathered granite

Tunnel face stability and ground movements induced by excavation are of significant concern in shallow tunneling through weak ground. In conjunction with other support systems, various pre-support measures are applied to reinforce the ground prior to excavation for ensuring tunnel crown stability an...

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Main Author:	Mohammad Yahya, Sarder
Format:	Thesis
Language:	English
Published:	2016
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/78977/1/SarderMohammadYahyaMFKA2016.pdf
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spelling	my-utm-ep.789772018-09-19T05:21:27Z Forepoling pre-support application in the shallow tunneling through weathered granite 2016 Mohammad Yahya, Sarder TA Engineering (General). Civil engineering (General) Tunnel face stability and ground movements induced by excavation are of significant concern in shallow tunneling through weak ground. In conjunction with other support systems, various pre-support measures are applied to reinforce the ground prior to excavation for ensuring tunnel crown stability and construction safety in general. Among them, forepoling is the simplest form of umbrella arch pre-support method which is widely used in tunneling application. Until now, very few studies addressed the effect of forepoling design parameters on crown stability of shallow tunnel constructed in weathered rock and no study is available for weathered granite. This leads to conservative and uneconomical designs of basic forepoling design parameters. This study aims at quantitative understanding through numerical parametric analysis regarding the behavior of forepoling pre-support design parameters that affect the crown stability of a shallow tunnel constructed in weathered granite. The effect of three design parameters - forepole length, installation angle and spacing on crown stability were investigated by using 3D finite element analysis program RS3 by Rocscience; using Pahang-Selangor raw water transfer tunnel project as a reference case. These parameters were then optimized considering total displacement and induced major principal stress at tunnel crown as evaluation indicator of crown stability. The results show that, the total displacement at tunnel crown increases by 0.64% when the forepole length was increased from 5 m to 9 m. The induced major principal stress at tunnel crown decreases by 1.02% when the length is varied from 3 m to 8 m. The total displacement at tunnel crown decreases by 0.23% when the installation angle of forepole is varied from 5° to 9°. From this study, it was found that length of 3 and 4 m; with angle of 5° to7°, and spacing of 300 mm are optimum forepoling design parameters under given tunneling condition. 2016 Thesis http://eprints.utm.my/id/eprint/78977/ http://eprints.utm.my/id/eprint/78977/1/SarderMohammadYahyaMFKA2016.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:106434 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) Mohammad Yahya, Sarder Forepoling pre-support application in the shallow tunneling through weathered granite
description	Tunnel face stability and ground movements induced by excavation are of significant concern in shallow tunneling through weak ground. In conjunction with other support systems, various pre-support measures are applied to reinforce the ground prior to excavation for ensuring tunnel crown stability and construction safety in general. Among them, forepoling is the simplest form of umbrella arch pre-support method which is widely used in tunneling application. Until now, very few studies addressed the effect of forepoling design parameters on crown stability of shallow tunnel constructed in weathered rock and no study is available for weathered granite. This leads to conservative and uneconomical designs of basic forepoling design parameters. This study aims at quantitative understanding through numerical parametric analysis regarding the behavior of forepoling pre-support design parameters that affect the crown stability of a shallow tunnel constructed in weathered granite. The effect of three design parameters - forepole length, installation angle and spacing on crown stability were investigated by using 3D finite element analysis program RS3 by Rocscience; using Pahang-Selangor raw water transfer tunnel project as a reference case. These parameters were then optimized considering total displacement and induced major principal stress at tunnel crown as evaluation indicator of crown stability. The results show that, the total displacement at tunnel crown increases by 0.64% when the forepole length was increased from 5 m to 9 m. The induced major principal stress at tunnel crown decreases by 1.02% when the length is varied from 3 m to 8 m. The total displacement at tunnel crown decreases by 0.23% when the installation angle of forepole is varied from 5° to 9°. From this study, it was found that length of 3 and 4 m; with angle of 5° to7°, and spacing of 300 mm are optimum forepoling design parameters under given tunneling condition.
format	Thesis
qualification_level	Master's degree
author	Mohammad Yahya, Sarder
author_facet	Mohammad Yahya, Sarder
author_sort	Mohammad Yahya, Sarder
title	Forepoling pre-support application in the shallow tunneling through weathered granite
title_short	Forepoling pre-support application in the shallow tunneling through weathered granite
title_full	Forepoling pre-support application in the shallow tunneling through weathered granite
title_fullStr	Forepoling pre-support application in the shallow tunneling through weathered granite
title_full_unstemmed	Forepoling pre-support application in the shallow tunneling through weathered granite
title_sort	forepoling pre-support application in the shallow tunneling through weathered granite
granting_institution	Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department	Faculty of Civil Engineering
publishDate	2016
url	http://eprints.utm.my/id/eprint/78977/1/SarderMohammadYahyaMFKA2016.pdf
_version_	1747818117843648512

Forepoling pre-support application in the shallow tunneling through weathered granite

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