Estimation of uniaxial compressive and tensile strength of rock material from gypsum deposits in the area of Knin

Briševac, Zlatko; Kujundžić, Trpimir; Macenić, Marija

doi:10.17559/tv-20150130152828

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…Therefore, the use of jaws with quite small contacts like those of the line loading condition are not suggested to prevent reaching excessive compressive stress concentrations that can make invalid failures. In the use of 15° jaw, compressive stresses were not found to be enough high for causing the invalid compressive failure as the ratio of the maximum compressive stress was 4 times of the maximum tensile stress [25][26][27].…”

Section: Discussionmentioning

confidence: 99%

Determination of Cohesion values of Rock Materials using Double Shear Jaws

Komurlu¹,

Demir²

2018

Period. Polytech. Civil Eng.

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IntroductionAlthough shear strength of rock materials is an important parameter for many different rock engineering applications, there is still a necessity for development of a standard method and details for determination of shear strength of rock materials. The conventional direct shear strength (DSS) test method suggested by International Society for Rock Mechanics and Rock Engineering (ISRM) and standards like ASTM D5607 are not a proper way to test high strength rock materials because of possible failure of cement mortar instead of rock core specimens [1][2][3]. The cement moulding method to hold specimens is more suitable for testing rock joints rather than intact rock materials. As another topic, the conventional DSS test has additional problems of impracticality in specimen preparation process including two steps cement mortar casting as seen in Fig 1. In this study, a practical test method for determination of cohesion values of rock materials is investigated to assess whether accurate strength values can be measured using double shear jaw (DSJ) which is a basic apparatus to test numerous specimens instead of only one specimen as in cement moulding method of holding. Within this purpose, new steel jaws for testing cohesion of rock materials were designed and manufactured in this study.Need for waiting the curing time of several days for holding specimens in the casted mortar method should be stated as another disadvantage of the conventional DSS test. As an important issue which prevents to measure the strength value under pure shearing, significant bending/tension effect is induced as the rock specimen loaded in the soft cement mortar. Having the bending effect in the specimen causes to measure smaller strength values than that determined under pure shearing condition [4][5][6][7]. In this study, a new method of using DSJ was investigated for the aim of having ideal loading condition. For the conventional DSS equipment in rock mechanics laboratories, manual load application by using the hydraulic jack is an additional lacking to cause a personal effect on the strength results. On the other hand, double shear jaws (DSJs) let specimens to be loaded vertically with a constant rate which can be supplied by the load controlled compressive equipment.

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Section: Discussionmentioning

confidence: 99%

Determination of Cohesion values of Rock Materials using Double Shear Jaws

Komurlu¹,

Demir²

2018

Period. Polytech. Civil Eng.

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“…Uniaxial compression tests of rock need to be carried out first before conducting direct shear tests of rock joints. Yet, in many cases, it is difficult to carry out physical tests, for which the estimation of uniaxial compressive strength for different rocks is an important research direction [40].…”

Section: Further Researchmentioning

confidence: 99%

Estimation of Shear Strength Parameters Considering Joint Roughness: A Stability Case Analysis of Bedding Rock Slopes in an Open-Pit Mine

Gao,

Wang,

Yin

et al. 2023

Applied Sciences

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This study aims to fully explore the influence of rock joint roughness in the slope stability analysis of an open mine. Therefore, based on the least squares parameter estimation method, a generalized shear strength parameter coupling roughness, which is used to evaluate a slope design, was established by a matching formula reflecting the relationship between the roughness coefficient and the shear strength parameter. Firstly, to verify and calibrate the model, physical direct shear tests were conducted on serrated rock joints, and the effect of roughness was analyzed qualitatively. The results show that an increase in tooth height increases the internal friction angle but decreases cohesion. Therefore, the rock joint direct shear test numerical model by PFC-2D was established and compared with the physical test curve, effectively verifying its correctness. The relationship between cohesion c and internal friction angle φ with roughness coefficient JRC was further quantified, and the new model was then fitted to characterize the relationship between roughness and shear strength parameters. This method is applied to the design optimization of an open pit mine slope. The new parameters are input to GeoSMA-3D, which is used to search for the key block of a bedding slope on an open-pit mine, to optimize the design of the slope.

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“…Accordingly, this fact must be considered when planning interventions in the natural environment [1]. Moisture is also known to affect the mechanical characteristics of brittle building materials [2] and gypsum [3][4][5], but the effects on stronger dimension stones should not be ignored. Dimension stone is a natural stone that is quarried and shaped into specific forms [6].…”

Section: Introductionmentioning

confidence: 99%

Saturation Influence on Reduction of Compressive Strength for Carbonate Dimension Stone in Croatia

Briševac,

Maričić,

Kujundžić

et al. 2023

Minerals

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Dimension stone is a valuable mineral raw material whose importance is increasing worldwide. According to its mineralogical and petrographical composition, Croatian dimension stone belongs to the carbonates, primarily limestones. As saturation influences the reduction of compressive strength, in this study, the relationship between the uniaxial compressive strength in the dry and saturated states is shown, which has a coefficient of determination of 0.9605. Models were created to estimate the compressive strength based on the values of water absorption, total porosity, and real density of the material from 26 sites, all determined according to the European standards EN 1936:2006 and EN 13755:2008. Thirty varieties of dimension stones were tested, and 150 values were collected from different tests. A dependence between the uniaxial compressive strength in the saturated state was established, including the explanation in which cases the correlation can be used to estimate the uniaxial compressive strength of carbonate dimension stones with a remarkably high degree of confidence (0.994 and 0.9374). In addition, the limitations of geomechanical estimation of the uniaxial compressive strength of rock material and its unsuitability for estimating of dimension stones construction are described.

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Estimation of uniaxial compressive and tensile strength of rock material from gypsum deposits in the area of Knin

Cited by 4 publications

References 8 publications

Determination of Cohesion values of Rock Materials using Double Shear Jaws

Determination of Cohesion values of Rock Materials using Double Shear Jaws

Estimation of Shear Strength Parameters Considering Joint Roughness: A Stability Case Analysis of Bedding Rock Slopes in an Open-Pit Mine

Saturation Influence on Reduction of Compressive Strength for Carbonate Dimension Stone in Croatia

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