Volume change measurement of a triaxial specimen by digital imaging

This project aimed to evaluate the feasibility of using digital image processing to determine the volume change of a soil specimen under isotropic consolidation. While more accurate methods of measuring the volume change of a sample may involve the use of liquid volume measurement...

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Main Author: Lim, Benjamin Jie Min.
Other Authors: Leong Eng Choon
Format: Final Year Project
Language:English
Published: 2013
Subjects:
Online Access:http://hdl.handle.net/10356/53858
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-538582023-03-03T17:26:19Z Volume change measurement of a triaxial specimen by digital imaging Lim, Benjamin Jie Min. Leong Eng Choon School of Civil and Environmental Engineering DRNTU::Engineering::Civil engineering::Geotechnical This project aimed to evaluate the feasibility of using digital image processing to determine the volume change of a soil specimen under isotropic consolidation. While more accurate methods of measuring the volume change of a sample may involve the use of liquid volume measurement for a saturated soil specimen or 3D laser scanning, digital image photogrammetry would be comparatively cheaper to obtain and simpler to conduct. However, accuracy of values obtained from such an approach remains to be further verified. This can be done by comparing the results obtained from the photogrammetry approach with any of the two more accurate methods mentioned above. If it can be shown that the results of volume change obtained from photogrammetry is within an acceptable margin of error, this could potentially be a reliable and economical method for volume measurement in laboratory tests, especially for unsaturated soil tests. This study involves the use of a fixed digital camera that can be revolved around the triaxial cell housing the specimen. By taking images of the specimen at different angles and at various time intervals, a three-dimensional specimen with (x,y,z) co-ordinates can be generated with an image processing software such as EOS PhotoModeler Scanner. Subsequently, the resulting model as a point cloud representation can be analysed using a thin layer method thereby obtaining a representative volume for each layer. Volume computation is subsequently a straightforward procedure of summing up all the layers. The study showed that photogrammetry is promising in measuring volume of a triaxial specimen. After relevant corrections, the errors shown using a digital camera and handphone camera are +/- 7 mm³ and +/- 15 mm³ respectively. The digital pressure volume controller (DPVC) used to validate the experimental results was found to suffer from compliance errors showing larger volume differences at low volume (low pressure) compared to high volume (high pressure). Bachelor of Engineering (Civil) 2013-06-07T08:50:32Z 2013-06-07T08:50:32Z 2013 2013 Final Year Project (FYP) http://hdl.handle.net/10356/53858 en Nanyang Technological University 64 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
spellingShingle DRNTU::Engineering::Civil engineering::Geotechnical
Lim, Benjamin Jie Min.
Volume change measurement of a triaxial specimen by digital imaging
description This project aimed to evaluate the feasibility of using digital image processing to determine the volume change of a soil specimen under isotropic consolidation. While more accurate methods of measuring the volume change of a sample may involve the use of liquid volume measurement for a saturated soil specimen or 3D laser scanning, digital image photogrammetry would be comparatively cheaper to obtain and simpler to conduct. However, accuracy of values obtained from such an approach remains to be further verified. This can be done by comparing the results obtained from the photogrammetry approach with any of the two more accurate methods mentioned above. If it can be shown that the results of volume change obtained from photogrammetry is within an acceptable margin of error, this could potentially be a reliable and economical method for volume measurement in laboratory tests, especially for unsaturated soil tests. This study involves the use of a fixed digital camera that can be revolved around the triaxial cell housing the specimen. By taking images of the specimen at different angles and at various time intervals, a three-dimensional specimen with (x,y,z) co-ordinates can be generated with an image processing software such as EOS PhotoModeler Scanner. Subsequently, the resulting model as a point cloud representation can be analysed using a thin layer method thereby obtaining a representative volume for each layer. Volume computation is subsequently a straightforward procedure of summing up all the layers. The study showed that photogrammetry is promising in measuring volume of a triaxial specimen. After relevant corrections, the errors shown using a digital camera and handphone camera are +/- 7 mm³ and +/- 15 mm³ respectively. The digital pressure volume controller (DPVC) used to validate the experimental results was found to suffer from compliance errors showing larger volume differences at low volume (low pressure) compared to high volume (high pressure).
author2 Leong Eng Choon
author_facet Leong Eng Choon
Lim, Benjamin Jie Min.
format Final Year Project
author Lim, Benjamin Jie Min.
author_sort Lim, Benjamin Jie Min.
title Volume change measurement of a triaxial specimen by digital imaging
title_short Volume change measurement of a triaxial specimen by digital imaging
title_full Volume change measurement of a triaxial specimen by digital imaging
title_fullStr Volume change measurement of a triaxial specimen by digital imaging
title_full_unstemmed Volume change measurement of a triaxial specimen by digital imaging
title_sort volume change measurement of a triaxial specimen by digital imaging
publishDate 2013
url http://hdl.handle.net/10356/53858
_version_ 1759856830679351296