An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks

Abstract Uniaxial Compressive test (UCS) results are essential in evaluation the values of Poisson’s ratio. However, according to the suggestion of the International Society for Rock Mechanics, Poisson’s ratio can be determined using three alternative methods: the secant, average and tangent. Applyi...

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Main Authors: Samad Narimani, László Kovács, Balázs Vásárhelyi
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-024-75892-2
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author Samad Narimani
László Kovács
Balázs Vásárhelyi
author_facet Samad Narimani
László Kovács
Balázs Vásárhelyi
author_sort Samad Narimani
collection DOAJ
description Abstract Uniaxial Compressive test (UCS) results are essential in evaluation the values of Poisson’s ratio. However, according to the suggestion of the International Society for Rock Mechanics, Poisson’s ratio can be determined using three alternative methods: the secant, average and tangent. Applying these methods causes discrepancies in the results; according to our experiences, the differences can be threefold or more. This paper aims to study the process of changes of Poisson’s ratio for intact rock during loading from micro-crack initiation to failure stage. The objective of this theoretical investigation is to establish a straightforward mathematical formulation between σ/σc and intact rock’s Poisson’s ratio value. To outline these changes forty two granite rocks were investigated from Bátaapáti radioactive waste repository (Hungary) and the calculation was performed by using the new formula from the beginning of loading till failure stage at UCS test. In the laboratory test program, Poisson’s ratio derived from standard tests varies with momentary stress; it steadily increases as stress rises until reaching the stress level causing unstable crack propagation. Additionally, the Poisson’s rate follows a linear increase with stress, up to the point of unstable crack propagation stress. The research demonstrated that the proposed equations provide competent values for the root mean squared error value (ranging from 0 to 0.04), the mean absolute percentage error (ranging from 0.6% to 18%) and the mean absolute error (ranging from 0 to 0.04). Contrary to previous ideas, our results suggest that the Poisson’s ratio is not a constant for rigid rocks.
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spelling doaj-art-f78b1680759d4ef58670aecbf9f4f0422025-08-20T03:53:12ZengNature PortfolioScientific Reports2045-23222025-05-0115111510.1038/s41598-024-75892-2An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocksSamad Narimani0László Kovács1Balázs Vásárhelyi2Department of Engineering Geology and Geotechnics, Budapest University of Technology and EconomicsRockStudy Ltd. (Komero Kft.)Department of Engineering Geology and Geotechnics, Budapest University of Technology and EconomicsAbstract Uniaxial Compressive test (UCS) results are essential in evaluation the values of Poisson’s ratio. However, according to the suggestion of the International Society for Rock Mechanics, Poisson’s ratio can be determined using three alternative methods: the secant, average and tangent. Applying these methods causes discrepancies in the results; according to our experiences, the differences can be threefold or more. This paper aims to study the process of changes of Poisson’s ratio for intact rock during loading from micro-crack initiation to failure stage. The objective of this theoretical investigation is to establish a straightforward mathematical formulation between σ/σc and intact rock’s Poisson’s ratio value. To outline these changes forty two granite rocks were investigated from Bátaapáti radioactive waste repository (Hungary) and the calculation was performed by using the new formula from the beginning of loading till failure stage at UCS test. In the laboratory test program, Poisson’s ratio derived from standard tests varies with momentary stress; it steadily increases as stress rises until reaching the stress level causing unstable crack propagation. Additionally, the Poisson’s rate follows a linear increase with stress, up to the point of unstable crack propagation stress. The research demonstrated that the proposed equations provide competent values for the root mean squared error value (ranging from 0 to 0.04), the mean absolute percentage error (ranging from 0.6% to 18%) and the mean absolute error (ranging from 0 to 0.04). Contrary to previous ideas, our results suggest that the Poisson’s ratio is not a constant for rigid rocks.https://doi.org/10.1038/s41598-024-75892-2UCSPoisson’s ratioGranitic rockCrack initiation stressCrack damage stress
spellingShingle Samad Narimani
László Kovács
Balázs Vásárhelyi
An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks
Scientific Reports
UCS
Poisson’s ratio
Granitic rock
Crack initiation stress
Crack damage stress
title An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks
title_full An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks
title_fullStr An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks
title_full_unstemmed An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks
title_short An innovative method to determine the stress-dependency of Poisson’s ratio of granitic rocks
title_sort innovative method to determine the stress dependency of poisson s ratio of granitic rocks
topic UCS
Poisson’s ratio
Granitic rock
Crack initiation stress
Crack damage stress
url https://doi.org/10.1038/s41598-024-75892-2
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