Spatial deformation estimation and long term structural health monitoring in underground engineering

The current understanding of geotechnical engineering and the development of underground structural health monitoring (SHM) methodology are still far behind the pace of the underground infrastructure development. The detection and estimation of time dependent displacement in tunnels and caverns have...

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Main Author: Sham, Wai Lun
Other Authors: Wong Ngai Yuen, Louis
Format: Theses and Dissertations
Language:English
Published: 2012
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Online Access:https://hdl.handle.net/10356/50723
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-507232023-03-03T19:17:16Z Spatial deformation estimation and long term structural health monitoring in underground engineering Sham, Wai Lun Wong Ngai Yuen, Louis Yang Yaowen School of Civil and Environmental Engineering NTU-MINDEF Protective Technology Research Centre DRNTU::Engineering::Civil engineering::Geotechnical DRNTU::Engineering::Civil engineering::Structures and design The current understanding of geotechnical engineering and the development of underground structural health monitoring (SHM) methodology are still far behind the pace of the underground infrastructure development. The detection and estimation of time dependent displacement in tunnels and caverns have always been in the top priority to research in the underground engineering sectors. It is important to resolve the black box for both long term and short term time-dependent deformation in tunnels to provide estimates for support installation time, design consideration and possible collapse detection. This thesis aims to initiate solutions to estimate and monitor the time dependent deformation in underground infrastructures. It begins with a detail summary of the factors that influence the time dependent deformation and the traditional SHM techniques in underground engineering. This is followed by the development of a new excavation advancement rate incorporated longitudinal displacement profile (ARLDP) to address the short term time-dependent displacement in tunnel caused by the excavation activities. The complementary introduction of the superimposed longitudinal displacement profile (SLDP) mapping technique utilizes onsite convergence measurement to provide quick and reliable estimates of the tunnel displacement profile. The highlight of this thesis comes from the initiation development of the real-time long-term spatial SHM for underground engineering. The development starts with describing the SHM system layout and investigating its feasibility of using the Brillouin Optical Time Domain Reflectometry (BOTDR) fiber optic sensing technique in underground engineering. A geometrical analysis is performed aiming to transform the strain measurement acquired from the BOTDR sensors to displacement data. The major challenges in this research are found in the calibration of the BOTDR strain sensor and the investigation of the BOTDR fiber optic sensor (FOS) installation method. Through series of experimental studies, the author has successfully addressed the technical and physical deficiency in employing the BOTDR FOS to develop the underground spatial SHM system. An onsite demonstration is also presented in this thesis to prove the feasibility and the possibility to develop such real-time long-term spatial SHM system for underground engineering. It is hope that this research would make a significant contribution and valuable reference for future development in underground engineering. Doctor of Philosophy (CEE) 2012-09-24T05:31:32Z 2012-09-24T05:31:32Z 2012 2012 Thesis Sham, W. L. (2012). Spatial deformation estimation and long term structural health monitoring in underground engineering. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/50723 10.32657/10356/50723 en 255 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::Geotechnical
DRNTU::Engineering::Civil engineering::Structures and design
spellingShingle DRNTU::Engineering::Civil engineering::Geotechnical
DRNTU::Engineering::Civil engineering::Structures and design
Sham, Wai Lun
Spatial deformation estimation and long term structural health monitoring in underground engineering
description The current understanding of geotechnical engineering and the development of underground structural health monitoring (SHM) methodology are still far behind the pace of the underground infrastructure development. The detection and estimation of time dependent displacement in tunnels and caverns have always been in the top priority to research in the underground engineering sectors. It is important to resolve the black box for both long term and short term time-dependent deformation in tunnels to provide estimates for support installation time, design consideration and possible collapse detection. This thesis aims to initiate solutions to estimate and monitor the time dependent deformation in underground infrastructures. It begins with a detail summary of the factors that influence the time dependent deformation and the traditional SHM techniques in underground engineering. This is followed by the development of a new excavation advancement rate incorporated longitudinal displacement profile (ARLDP) to address the short term time-dependent displacement in tunnel caused by the excavation activities. The complementary introduction of the superimposed longitudinal displacement profile (SLDP) mapping technique utilizes onsite convergence measurement to provide quick and reliable estimates of the tunnel displacement profile. The highlight of this thesis comes from the initiation development of the real-time long-term spatial SHM for underground engineering. The development starts with describing the SHM system layout and investigating its feasibility of using the Brillouin Optical Time Domain Reflectometry (BOTDR) fiber optic sensing technique in underground engineering. A geometrical analysis is performed aiming to transform the strain measurement acquired from the BOTDR sensors to displacement data. The major challenges in this research are found in the calibration of the BOTDR strain sensor and the investigation of the BOTDR fiber optic sensor (FOS) installation method. Through series of experimental studies, the author has successfully addressed the technical and physical deficiency in employing the BOTDR FOS to develop the underground spatial SHM system. An onsite demonstration is also presented in this thesis to prove the feasibility and the possibility to develop such real-time long-term spatial SHM system for underground engineering. It is hope that this research would make a significant contribution and valuable reference for future development in underground engineering.
author2 Wong Ngai Yuen, Louis
author_facet Wong Ngai Yuen, Louis
Sham, Wai Lun
format Theses and Dissertations
author Sham, Wai Lun
author_sort Sham, Wai Lun
title Spatial deformation estimation and long term structural health monitoring in underground engineering
title_short Spatial deformation estimation and long term structural health monitoring in underground engineering
title_full Spatial deformation estimation and long term structural health monitoring in underground engineering
title_fullStr Spatial deformation estimation and long term structural health monitoring in underground engineering
title_full_unstemmed Spatial deformation estimation and long term structural health monitoring in underground engineering
title_sort spatial deformation estimation and long term structural health monitoring in underground engineering
publishDate 2012
url https://hdl.handle.net/10356/50723
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