Measuring vs30 using surface wave tests

Given that Singapore has adopted the Eurocode since 1st April 2013, there is a need to test out methods to obtain the average shear wave velocity or VS as it is one of the main parameters used in the classification of ground types. The usual parameter involving VS is the VS,30 or the averag...

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Main Author: Chau, Glenn Wen Hon
Other Authors: Leong Eng Choon
Format: Final Year Project
Language:English
Published: 2014
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Online Access:http://hdl.handle.net/10356/61202
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-612022023-03-03T16:59:59Z Measuring vs30 using surface wave tests Chau, Glenn Wen Hon Leong Eng Choon School of Civil and Environmental Engineering DRNTU::Engineering Given that Singapore has adopted the Eurocode since 1st April 2013, there is a need to test out methods to obtain the average shear wave velocity or VS as it is one of the main parameters used in the classification of ground types. The usual parameter involving VS is the VS,30 or the average shear wave velocity of the top 30m of soil layer. This project focuses on a specific type of site test, the continuous surface wave system (CSWS) test. This is a non-invasive test method that involves a vertically oscillating mass vibrator, geophone receivers, a CPU and a vibrator control unit. Seismic waves are sent into the ground by the vibrator and the geophone receivers pick up the corresponding phase angles. The receivers are placed at different offset distances during the course of each site test to ensure homogeneity in the ground layers. The objective of the field tests is to acquire parameters that will aid in the calculation of the shear wave velocity profile, which will lead to the VS,30 value being able to be obtained. The results from six test sites in Singapore were taken and analyzed. In order to produce the shear wave velocity profile, inversion process had to be used and for this project, the weighted average velocity (WAVe) method was employed. Also, it has to be noted that for all the test sites, the depth of penetration of the seismic waves into the ground did not reach 30m. As such, the VS,30 value could not be obtained directly but instead, a correlation method had to be used to estimate the VS,30 value. It was shown that although both the VS,5 and VS,10 values could be used to estimate the VS,30, they were not very accurate as three out of the six values were out of the historical data range of their respective sites. It was seen that while the CSWS tests were not a very accurate measure to estimate the VS,30 values, it was still useful as a rough guide to obtain the ground classification type. Bachelor of Engineering 2014-06-06T03:20:47Z 2014-06-06T03:20:47Z 2014 2014 Final Year Project (FYP) http://hdl.handle.net/10356/61202 en Nanyang Technological University 54 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
spellingShingle DRNTU::Engineering
Chau, Glenn Wen Hon
Measuring vs30 using surface wave tests
description Given that Singapore has adopted the Eurocode since 1st April 2013, there is a need to test out methods to obtain the average shear wave velocity or VS as it is one of the main parameters used in the classification of ground types. The usual parameter involving VS is the VS,30 or the average shear wave velocity of the top 30m of soil layer. This project focuses on a specific type of site test, the continuous surface wave system (CSWS) test. This is a non-invasive test method that involves a vertically oscillating mass vibrator, geophone receivers, a CPU and a vibrator control unit. Seismic waves are sent into the ground by the vibrator and the geophone receivers pick up the corresponding phase angles. The receivers are placed at different offset distances during the course of each site test to ensure homogeneity in the ground layers. The objective of the field tests is to acquire parameters that will aid in the calculation of the shear wave velocity profile, which will lead to the VS,30 value being able to be obtained. The results from six test sites in Singapore were taken and analyzed. In order to produce the shear wave velocity profile, inversion process had to be used and for this project, the weighted average velocity (WAVe) method was employed. Also, it has to be noted that for all the test sites, the depth of penetration of the seismic waves into the ground did not reach 30m. As such, the VS,30 value could not be obtained directly but instead, a correlation method had to be used to estimate the VS,30 value. It was shown that although both the VS,5 and VS,10 values could be used to estimate the VS,30, they were not very accurate as three out of the six values were out of the historical data range of their respective sites. It was seen that while the CSWS tests were not a very accurate measure to estimate the VS,30 values, it was still useful as a rough guide to obtain the ground classification type.
author2 Leong Eng Choon
author_facet Leong Eng Choon
Chau, Glenn Wen Hon
format Final Year Project
author Chau, Glenn Wen Hon
author_sort Chau, Glenn Wen Hon
title Measuring vs30 using surface wave tests
title_short Measuring vs30 using surface wave tests
title_full Measuring vs30 using surface wave tests
title_fullStr Measuring vs30 using surface wave tests
title_full_unstemmed Measuring vs30 using surface wave tests
title_sort measuring vs30 using surface wave tests
publishDate 2014
url http://hdl.handle.net/10356/61202
_version_ 1759853492439089152