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

Abstract

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.

Historical Use of the Ashlar Limestone at Piatra Roșie Dacian Fortress; Interdisciplinary Approach in a World Heritage Site

“…The compression strength value is normal for this type of limestone [24,25], but the flexural strengths obtained on the specimens are lower than the expected values. In order to compensate the potential fragility, the ancient masons applied special constructions techniques.…”

“…The hill of the fortress, with its particular shape and reddish rocky slopes, has constituted from the very beginning an important visual landmark. The first written testimony of this toponymy dates from the 15th century [1] (p. 24), but it is definitely older. The ruins were probably known by the locals and by the passing shepherds, but the first documents mentioning it date from the 19th century [5] (p. 317).…”

“…The natural way in which these stones have kept their resistance properties was, in some cases, the deposition of a clayey and biomineral layer that filled the small cavities and covered the surface of the blocks (Figures 8b and 12) [21] (pp. [23][24][25], insulating the interior and protecting it from significant chemical transformations and physical degradation [22] (pp. 61-65).…”

Physico-Mechanical Characteristics of Limestone Blocks from the Republic of Moldova

“…In order to understand more deeply the characteristics of the limestone extracted on the territory of Moldova, the compressive strength of different types of limestone was analysed. The summary of the data presented by researchers in this field (28)(29)(30)(31)(32)(33)(34) is proposed in Table 5. Overlapping data shows that the compressive strength of limestone blocks in Moldova is of mixed composition between fossil limestone and oolitic limestone, and combining these two types of limestone has a higher strength.…”

Investigation of the usability of Wide Wheel Abrasion test on rock core samples and proposal of a core abrasion index

“…and there are studies to compare Leeb hardness with different hardness measurement methods(Verwaal and Mulder 1993; Meulenkamp and Alvarez Grima, 1999;Kawasaki et al 2002;Aoki and Matsukura 2008;Daniels et al 2012;Güneş Yılmaz, 2013;Lee et al 2014;Güneş Yılmaz and Göktan 2019;Corkum et al 2018; Desernaud et al 2019;Çelik and Çobanoğlu 2019;Aldeeky et al 2020;Gomez-Heras et al 2020;Benavente et al 2021). It was demonstrated by various researchers that the Leeb hardness is used with great success in estimating the UCS values of rocks.…”