A validation study for the estimation of uniaxial compressive strength based on index tests

Uniaxial compressive strength (UCS) is one of the crucial parameters controlling the strength of rock masses (Hu et al. 2012). A reliable and direct measurement of this parameter in the laboratory requires well-prepared samples and certified testing apparatus (Heidari et al. 2012). As an indirect me...

Full description

Saved in:
Bibliographic Details
Main Authors: Kong, Fanmeng, Shang, Junlong
Other Authors: School of Civil and Environmental Engineering
Format: Article
Language:English
Published: 2020
Subjects:
Online Access:https://hdl.handle.net/10356/141459
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-141459
record_format dspace
spelling sg-ntu-dr.10356-1414592020-06-08T09:07:50Z A validation study for the estimation of uniaxial compressive strength based on index tests Kong, Fanmeng Shang, Junlong School of Civil and Environmental Engineering Nanyang Centre for Underground Space Engineering::Civil engineering Uniaxial Compressive Strength Point Load Index Uniaxial compressive strength (UCS) is one of the crucial parameters controlling the strength of rock masses (Hu et al. 2012). A reliable and direct measurement of this parameter in the laboratory requires well-prepared samples and certified testing apparatus (Heidari et al. 2012). As an indirect method, index tests have been widely used to estimate the UCS of rock, especially in the field. The index tests can be performed using simple equipment such as portable point load testers and Schmidt hammers. Up to now, the relationship between UCS and the results of index tests has been widely discussed (Hoek 1977; Aggistalis et al. 1996; Fener et al. 2005; Karaman and Kesimal 2015). The validity of the index tests, however, remains poorly understood; results of the tests may vary due to lithological heterogeneity mainly arising from geological bedding and schistosity, grain size variation and micro-fractures. For example, point load test results may vary significantly (by a factor up to 2) when samples drilled with different orientations relative to bedding planes are used (Broch 1983). Broch (1983) pointed out that the most reliable strength index can be obtained when samples are drilled normal to bedding planes. In addition, when a tested rock surface contains coarse grains with sizes comparable to the plunger tip diameter, the readings of Schmidt hammers can vary significantly, depending on their strength relative to the dominant grain size of the tested rock (Aydin 2009). Situations become worse when micro-fractures exist (unseen by the naked eye). It is therefore questionable about the validity of the index tests in the estimation of UCS, because the variation of the index test results can be attributed to (1) lithological heterogeneity of the tested rock samples (as described above) and (2) the validity of the index tests themselves. 2020-06-08T09:07:50Z 2020-06-08T09:07:50Z 2018 Journal Article Kong, F., & Shang, J. (2018). A validation study for the estimation of uniaxial compressive strength based on index tests. Rock Mechanics and Rock Engineering, 51(7), 2289-2297. doi:10.1007/s00603-018-1462-9 0723-2632 https://hdl.handle.net/10356/141459 10.1007/s00603-018-1462-9 2-s2.0-85044382384 7 51 2289 2297 en Rock Mechanics and Rock Engineering © 2018 Springer-Verlag GmbH Austria, part of Springer Nature. All rights reserved.
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Engineering::Civil engineering
Uniaxial Compressive Strength
Point Load Index
spellingShingle Engineering::Civil engineering
Uniaxial Compressive Strength
Point Load Index
Kong, Fanmeng
Shang, Junlong
A validation study for the estimation of uniaxial compressive strength based on index tests
description Uniaxial compressive strength (UCS) is one of the crucial parameters controlling the strength of rock masses (Hu et al. 2012). A reliable and direct measurement of this parameter in the laboratory requires well-prepared samples and certified testing apparatus (Heidari et al. 2012). As an indirect method, index tests have been widely used to estimate the UCS of rock, especially in the field. The index tests can be performed using simple equipment such as portable point load testers and Schmidt hammers. Up to now, the relationship between UCS and the results of index tests has been widely discussed (Hoek 1977; Aggistalis et al. 1996; Fener et al. 2005; Karaman and Kesimal 2015). The validity of the index tests, however, remains poorly understood; results of the tests may vary due to lithological heterogeneity mainly arising from geological bedding and schistosity, grain size variation and micro-fractures. For example, point load test results may vary significantly (by a factor up to 2) when samples drilled with different orientations relative to bedding planes are used (Broch 1983). Broch (1983) pointed out that the most reliable strength index can be obtained when samples are drilled normal to bedding planes. In addition, when a tested rock surface contains coarse grains with sizes comparable to the plunger tip diameter, the readings of Schmidt hammers can vary significantly, depending on their strength relative to the dominant grain size of the tested rock (Aydin 2009). Situations become worse when micro-fractures exist (unseen by the naked eye). It is therefore questionable about the validity of the index tests in the estimation of UCS, because the variation of the index test results can be attributed to (1) lithological heterogeneity of the tested rock samples (as described above) and (2) the validity of the index tests themselves.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Kong, Fanmeng
Shang, Junlong
format Article
author Kong, Fanmeng
Shang, Junlong
author_sort Kong, Fanmeng
title A validation study for the estimation of uniaxial compressive strength based on index tests
title_short A validation study for the estimation of uniaxial compressive strength based on index tests
title_full A validation study for the estimation of uniaxial compressive strength based on index tests
title_fullStr A validation study for the estimation of uniaxial compressive strength based on index tests
title_full_unstemmed A validation study for the estimation of uniaxial compressive strength based on index tests
title_sort validation study for the estimation of uniaxial compressive strength based on index tests
publishDate 2020
url https://hdl.handle.net/10356/141459
_version_ 1681059048202436608