THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK

The uniaxial compressive strength (UCS), Young’s modulus (E) and Poisson’s ratio (ν) of intact rock depend on the cylindrical specimen shape tolerances (flatness of ends R, their parallelism P and perpendicularity to the specimen axis O). Today’s specimen acceptance criteria (allowable R/P/O) are ba...

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Main Authors: Nataša Štambuk Cvitanović, Boris Kavur, Ivan Vrkljan, Predrag Miščević
Format: Article
Language:English
Published: University of Zagreb 2025-01-01
Series:Rudarsko-geološko-naftni Zbornik
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Online Access:https://hrcak.srce.hr/file/481994
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author Nataša Štambuk Cvitanović
Boris Kavur
Ivan Vrkljan
Predrag Miščević
author_facet Nataša Štambuk Cvitanović
Boris Kavur
Ivan Vrkljan
Predrag Miščević
author_sort Nataša Štambuk Cvitanović
collection DOAJ
description The uniaxial compressive strength (UCS), Young’s modulus (E) and Poisson’s ratio (ν) of intact rock depend on the cylindrical specimen shape tolerances (flatness of ends R, their parallelism P and perpendicularity to the specimen axis O). Today’s specimen acceptance criteria (allowable R/P/O) are based on scarce research data from the 1970s that mostly relate to UCS without considering the rock strength category (worst case scenario). They are also very strict and, in some cases, difficult to implement, requiring engineering judgment. To increase reliability and facilitate judgment of specimen acceptability, this study investigates the influence of shape tolerances on all UCS/E/ν properties and related energy dissipation properties (total, elastic and dissipated energy) for limestone and comparable medium-strength rock with UCS around 100-150 MPa. Ninety specimens were prepared with target (wider) shape tolerances (R up to 0.5 mm; P, O up to 2°) using specially developed equipment for accurate R/P/O determination. These specimens were further tested in uniaxial compression with several relevant measurement settings and all mechanical and energy dissipation properties were determined. From many experimental results and additional statistical/numerical/energy analyses, reliable behaviour models for UCS/E/ν dependence on R/P/O have been established that can be further used to assess the consequences of shape tolerances and specimen acceptability. If limits of natural variability for ‘ideal’ specimens are applied to these models, critical tolerances that reduce the existing requirements are obtained (e.g. R = 0.08 mm instead of 0.05 mm), which are proposed as supplementary to optimize the testing process for medium-strength rocks.
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spelling doaj-art-8e01d349b81241c5ad2ce0c55efc990e2025-08-20T03:17:43ZengUniversity of ZagrebRudarsko-geološko-naftni Zbornik0353-45291849-04092025-01-0140316719310.17794/rgn.2025.3.12THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCKNataša Štambuk Cvitanović0Boris Kavur1Ivan Vrkljan2Predrag Miščević3University of Split, Faculty of Civil Engineering, Architecture and Geodesy, Matice hrvatske 15, Split, CroatiaUniversity of Zagreb, Faculty of Geotechnical Engineering, Hallerova aleja 7, Varaždin, CroatiaUniversity of Rijeka, Faculty of Civil Engineering, Radmile Matejčić 3, Rijeka, CroatiaUniversity of Split, Faculty of Civil Engineering, Architecture and Geodesy, Matice hrvatske 15, Split, CroatiaThe uniaxial compressive strength (UCS), Young’s modulus (E) and Poisson’s ratio (ν) of intact rock depend on the cylindrical specimen shape tolerances (flatness of ends R, their parallelism P and perpendicularity to the specimen axis O). Today’s specimen acceptance criteria (allowable R/P/O) are based on scarce research data from the 1970s that mostly relate to UCS without considering the rock strength category (worst case scenario). They are also very strict and, in some cases, difficult to implement, requiring engineering judgment. To increase reliability and facilitate judgment of specimen acceptability, this study investigates the influence of shape tolerances on all UCS/E/ν properties and related energy dissipation properties (total, elastic and dissipated energy) for limestone and comparable medium-strength rock with UCS around 100-150 MPa. Ninety specimens were prepared with target (wider) shape tolerances (R up to 0.5 mm; P, O up to 2°) using specially developed equipment for accurate R/P/O determination. These specimens were further tested in uniaxial compression with several relevant measurement settings and all mechanical and energy dissipation properties were determined. From many experimental results and additional statistical/numerical/energy analyses, reliable behaviour models for UCS/E/ν dependence on R/P/O have been established that can be further used to assess the consequences of shape tolerances and specimen acceptability. If limits of natural variability for ‘ideal’ specimens are applied to these models, critical tolerances that reduce the existing requirements are obtained (e.g. R = 0.08 mm instead of 0.05 mm), which are proposed as supplementary to optimize the testing process for medium-strength rocks.https://hrcak.srce.hr/file/481994cylindrical rock test specimensshape tolerancesmechanical propertiesenergy dissipation properties
spellingShingle Nataša Štambuk Cvitanović
Boris Kavur
Ivan Vrkljan
Predrag Miščević
THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK
Rudarsko-geološko-naftni Zbornik
cylindrical rock test specimens
shape tolerances
mechanical properties
energy dissipation properties
title THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK
title_full THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK
title_fullStr THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK
title_full_unstemmed THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK
title_short THE EFFECTS OF TEST SPECIMEN SHAPE TOLERANCES ON DETERMINING THE MECHANICAL AND ENERGY DISSIPATION PROPERTIES OF LIMESTONE ROCK
title_sort effects of test specimen shape tolerances on determining the mechanical and energy dissipation properties of limestone rock
topic cylindrical rock test specimens
shape tolerances
mechanical properties
energy dissipation properties
url https://hrcak.srce.hr/file/481994
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