Estimating Rock Strength From Non-Destructive Strength Testing (EQUOTIP) and Related Benefits

Hujer, Wolfgang; Finkbeiner, Thomas; Persaud, M.

doi:10.3997/2214-4609.20140444

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…The single impacts method involves the firing of multiple randomly located single impacts across the sample surface (Verwaal & Mulder, 1993) and taking the calculated mean average of these individual impact values as the characteristic hardness. This method has been applied to a number of studies using the Equotip to evaluate rock properties (e.g., Verwaal & Mulder, 1993;Matsukura, 2007 andFeal-Pérez & Blanco-Chao, 2012;Coombes et al, 2013;Hujer et al, 2014;Asiri et al, 2016). Although no standardised number of impacts has been established, the single impact method allows for the natural heterogeneity of the rock mass to be incorporated into the result.…”

Section: Equotip Rebound Hardness Testingmentioning

confidence: 99%

A pilot study investigating the rapid estimation of intact dry density of chalk using low impact energy hardness measurements taken with an Equotip Leeb hardness tester

Thrower

Barlow

Moore

et al. 2022

QJEGH

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Intact dry density (IDD) is a key parameter for characterising the rock mass behaviour of chalk and is often the main classification property reported for engineering design. The role of IDD in coastal chalk settings has been discussed in literature as an important rock control for coastal cliff recession behaviour. This study demonstrates a tool that can reliably estimate the IDD of chalk samples. Originally developed for testing sheet steel materials, the Equotip has been shown to be adaptable for geological applications and the results of this study show that the Equotip can be used to derive a surface hardness value of dry chalk samples that has a positive correlation with IDD. Furthermore, the results show that the device is sensitive to the anisotropy of chalk and that testing undertaken in the diametral orientation give more accurate correlations. The results of this study also show that the Equotip is sensitive to environmental setting and the effects of weathering, giving a separate correlation for samples collected along the Sussex coastline to those obtained inland. A statistical assessment of the results shows that a characteristic hardness within an acceptable margin of error can be achieved from an optimal number of single impacts.

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Section: Equotip Rebound Hardness Testingmentioning

confidence: 99%

A pilot study investigating the rapid estimation of intact dry density of chalk using low impact energy hardness measurements taken with an Equotip Leeb hardness tester

Thrower

Barlow

Moore

et al. 2022

QJEGH

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show abstract

“…[26][27][28] Likewise, existing research shows accurate correlations between Leeb hardness and UCS. [29][30][31][32][33] Therefore, Leeb hardness was selected as the surface rock hardness technique to estimate UCS. Rebound hardness techniques are sensitive to rock surface properties, including superficial alterations, superficial crusts, etc., which can interfere in the estimation of UCS of the whole sample.…”

Section: Introductionmentioning

confidence: 99%

Improving uniaxial compressive strength estimation of carbonate sedimentary rocks by combining minimally invasive and non-destructive techniques

Benavente

Fort

Gómez-Heras

2021

International Journal of Rock Mechanics and Mining Sciences

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Uniaxial compressive strength (UCS) is the most used parameter to measure rock strength. However, restrictions in sampling large volume of material, the need of very large set of results and onsite characterisation of UCS nondestructively are requirements in many scientific and engineering investigations. The estimation of UCS from a single non-destructive or minimally invasive technique (NDT) may result incomplete because each NDT is sensitive to different compositional and textural factors.This paper combines open porosity, P-wave velocity, Leeb hardness and micro-drilling resistance force to estimate USC for a wide range of carbonate sedimentary rock types with different petrographic characteristics. Results reveal that mineralogical composition significatively affects micro-drilling resistance force profiles and Pwave velocity values, especially for quartz-bearing rocks. In addition, texture controls substantially the reproducibility of tests sensible to rock surface properties, such as Leeb hardness and micro-drilling resistance force.Fifteen simple and multiple expressions for UCS are fitted. Linear expressions have shown better coefficients of determination (R 2 ) than non-linear equations because of the linearity shown by individual parameters. Curve fitting improves as the number of petrophysical parameters increase in the multiple linear regression analysis. The best correlation is found when the equation incorporates all the mechanical parameters obtained nondestructively as well as open porosity (R 2 = 0.910). Leeb hardness is always the most significant variable of the fitted regressions and its addition into multiple linear equations causes an increase of R 2 . Open porosity also improves R 2 whereas drilling force and P-wave velocity have a lower statistical weight in the expressions. The UCS estimation from all NDT, without considering open porosity, shows a good correlation (R 2 = 0.899), which presents the advantage that they can be obtained non-destructively with portable equipment and can provide a numerous set of results at relatively low cost.

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Controls of lithology and degree of fracturing on the in-situ estimation of rock mass hardness using the Equotip hardness tester

Mammoliti,

Ciattoni,

Francioni

et al. 2024

Bull Eng Geol Environ

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Estimating Rock Strength From Non-Destructive Strength Testing (EQUOTIP) and Related Benefits

Cited by 4 publications

References 2 publications

A pilot study investigating the rapid estimation of intact dry density of chalk using low impact energy hardness measurements taken with an Equotip Leeb hardness tester

A pilot study investigating the rapid estimation of intact dry density of chalk using low impact energy hardness measurements taken with an Equotip Leeb hardness tester

Improving uniaxial compressive strength estimation of carbonate sedimentary rocks by combining minimally invasive and non-destructive techniques

Controls of lithology and degree of fracturing on the in-situ estimation of rock mass hardness using the Equotip hardness tester

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