@article{MTMT:34234011,
	title = {Estimation of the Poisson's Ratio of the Rock Mass},
	url = {https://m2.mtmt.hu/api/publication/34234011},
	author = {Narimani Ghourtlar, Samad and Davarpanah, Seyed Morteza and Vásárhelyi, Balázs},
	doi = {10.3311/PPci.22689},
	journal-iso = {PERIOD POLYTECH CIV ENG},
	journal = {PERIODICA POLYTECHNICA-CIVIL ENGINEERING},
	volume = {68},
	unique-id = {34234011},
	issn = {0553-6626},
	abstract = {The value of Poisson's ratio is a crucial parameter in rock mechanics and engineering for both intact rock and rock mass. Poisson's ratio has not gotten the attention it merits compared to other essential mechanical characteristics of intact rock and rock mass. Limited relationships exist between rock mass classification systems (such as RMR, RMQR, Q, and GSI) and Poisson's ratio. This paper provides a comprehensive review of models proposed by various researchers for estimating Poisson's ratio for rock mass. The different methods are compared, and new general equations are derived. The results indicate that the Poisson's ratio value of rock mass is inversely proportional to its quality and strength and depends on the Poisson's ratio value of the intact rock. Specifically, a linear equation is obtained using the RMR or GSI system, showing that the Poisson's ratio increases as the quality and strength of the rock mass decrease. The Q system has a logarithmic link between the rock mass quality and Poisson's ratio. It should be noted that the derived equations are applicable only under the assumption of a homogeneous isotropic rock mass.},
	keywords = {STRESS; YOUNGS MODULUS; strength; Rock mass classification; Rock mass; Poisson's ratio},
	year = {2024},
	eissn = {1587-3773},
	pages = {274-288},
	orcid-numbers = {Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@inproceedings{MTMT:34184154,
	title = {Rock mass characterization during the construction of a twin-tube motorway tunnel in Hungary},
	url = {https://m2.mtmt.hu/api/publication/34184154},
	author = {Somodi, Gábor and Borsody, János and Krupa, Ágnes and Petrik, Krisztián and Vásárhelyi, Balázs},
	booktitle = {Proceedings of the ISRM 15th International Congress on Rock Mechanics and Rock Engineering & 72nd Geomechanics Colloquium},
	unique-id = {34184154},
	year = {2023},
	pages = {854-859},
	orcid-numbers = {Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@inproceedings{MTMT:34184044,
	title = {Characterization of Poisson’s ratio and Elastic Modulus of granitic rocks: from micro-crack initiation to failure},
	url = {https://m2.mtmt.hu/api/publication/34184044},
	author = {Narimani Ghourtlar, Samad and Davarpanah, Seyed Morteza and Kovács, László and Vásárhelyi, Balázs},
	booktitle = {Proceedings of the ISRM 15th International Congress on Rock Mechanics and Rock Engineering & 72nd Geomechanics Colloquium},
	unique-id = {34184044},
	year = {2023},
	pages = {2508-2513},
	orcid-numbers = {Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@article{MTMT:34093135,
	title = {Geological Strength Index Relationships with the Q-System and Q-Slope},
	url = {https://m2.mtmt.hu/api/publication/34093135},
	author = {Narimani Ghourtlar, Samad and Davarpanah, Seyed Morteza and Bar, Neil and Török, Ákos and Vásárhelyi, Balázs},
	doi = {10.3390/su151411233},
	journal-iso = {SUSTAINABILITY-BASEL},
	journal = {SUSTAINABILITY},
	volume = {15},
	unique-id = {34093135},
	abstract = {The Q-system and Q-slope are empirical methods developed for classifying and assessing rock masses for tunneling, underground mining, and rock slope engineering. Both methods have been used extensively to guide appropriate ground support design for underground excavations and stable angles for rock slopes. Using datasets obtained from igneous, sedimentary, and metamorphic rock slopes from various regions worldwide, this research investigates different relationships between the geological strength index (GSI) and the Q-system and Q-slope. It also presents relationships between chart-derived GSI with GSI estimations from RMR89 and Q' during drill core logging or traverse mapping. Statistical analysis was used to assess the reliability of the suggested correlations to determine the validity of the produced equations. The research demonstrated that the proposed equations provide appropriate values for the root mean squared error value (RMSE), the mean absolute percentage error (MAPE), the mean absolute error (MAE), and the coefficient of determination (R-squared). These relationships provide appropriate regression coefficients, and it was identified that correlations were stronger when considering metamorphic rocks rather than other rocks. Moreover, considering all rock types together, achieved correlations are remarkable.},
	keywords = {MECHANICAL-PROPERTIES; Rock mass classification; Environmental Sciences; GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY; Q-SYSTEM; Q-slope},
	year = {2023},
	eissn = {2071-1050},
	orcid-numbers = {Török, Ákos/0000-0002-5394-4510; Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@article{MTMT:33766973,
	title = {Variation of Elastic Stiffness Parameters of Granitic Rock during Loading in Uniaxial Compressive Test},
	url = {https://m2.mtmt.hu/api/publication/33766973},
	author = {Narimani Ghourtlar, Samad and Davarpanah, Seyed Morteza and Kovács, László and Vásárhelyi, Balázs},
	doi = {10.3390/applmech4020025},
	journal-iso = {APPLI MECH},
	journal = {APPLIED MECHANICS},
	volume = {4},
	unique-id = {33766973},
	abstract = {Any rock mechanics’ design inherently involves determining the deformation characteristics of the rock material. The purpose of this study is to offer equations for calculating the values of bulk modulus (K), elasticity modulus (E), and rigidity modulus (G) throughout the loading of the sample until failure. Also, the Poisson’s ratio, which is characterized from the stress–strain curve, has a significant effect on the rigidity and bulk moduli. The results of a uniaxial compressive (UCS) test on granitic rocks from the Morágy (Hungary) radioactive waste reservoir site were gathered and examined for this purpose. The fluctuation of E, G, and K has been the subject of new linear and nonlinear connections. The proposed equations are parabolic in all of the scenarios for the Young’s modulus and shear modulus, the study indicates. Furthermore, the suggested equations for the bulk modulus in the secant, average, and tangent instances are also nonlinear. Moreover, we achieved correlations with a high determination factor for E, G, and K in three different scenarios: secant, tangent, and average. It is particularly intriguing to observe that the elastic stiffness parameters exhibit strong correlation in the results.},
	year = {2023},
	eissn = {2673-3161},
	pages = {445-459},
	orcid-numbers = {Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@{MTMT:33766955,
	title = {A kőzettestek töredezettségének minősítése az RQD mérőszám újraértelmezésével [Fracture density rating of rock mass through reinterpreting the determination of RQD (Rock Quality Designation) value]},
	url = {https://m2.mtmt.hu/api/publication/33766955},
	author = {Vásárhelyi, Balázs and Somodi, Gábor},
	booktitle = {Kőzetmechanika és termodinamika [Rock mechanics and thermodynamics]},
	unique-id = {33766955},
	year = {2023},
	pages = {163-168},
	orcid-numbers = {Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@book{MTMT:33766834,
	title = {Kőzetmechanika és termodinamika [Rock mechanics and thermodynamics]},
	url = {https://m2.mtmt.hu/api/publication/33766834},
	isbn = {9786158015783},
	editor = {Takács, Donát M. and Ván, Péter and Vásárhelyi, Balázs},
	publisher = {Egyesület a Tudomány és Technológia Egységéért},
	unique-id = {33766834},
	year = {2023},
	orcid-numbers = {Takács, Donát M./0000-0002-8463-745X; Ván, Péter/0000-0002-9396-4073; Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@article{MTMT:33714477,
	title = {A zsámbéki Öregtemplom építőanyagának vizsgálata: esettanulmány},
	url = {https://m2.mtmt.hu/api/publication/33714477},
	author = {Lógó, Benedek András and Vásárhelyi, Balázs},
	doi = {10.1556/096.2023.00082},
	journal-iso = {ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY},
	journal = {ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY},
	volume = {51},
	unique-id = {33714477},
	issn = {0013-9661},
	abstract = {A zsámbéki romtemplom az ország egyik legismertebb műemléke. Története során számos alkalommal átépítették, felújították már mielőtt lepusztult volna. Azóta már több terv is született, hogy milyen irányba kellene a rom hasznosítását terelni. Ezek széles variációkkal rendelkeztek, attól kezdve, hogy legfeljebb csak állagmegóvás legyen egészen odáig, hogy teljesen visszaépítsék. Időről időre előkerül mindig ez a kérdés. Ez az esettanulmány is egy tervezés előtti felmérés keretén belül született. A tanulmány a rom építőanyagainak, főleg az eredeti kőanyag és habarcs vizsgálataival, azok mostani állapotával foglalkozik. Egy átfogó felmérés is készült a templomról, amely feltérképezi, hogy hol, milyen anyagból áll a szerkezet.},
	year = {2023},
	eissn = {1588-2764},
	pages = {25-37},
	orcid-numbers = {Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@article{MTMT:33581825,
	title = {Brittle-ductile transition stress of different rock types and its relationship with uniaxial compressive strength and Hoek–Brown material constant (mi)},
	url = {https://m2.mtmt.hu/api/publication/33581825},
	author = {Davarpanah, Seyed Morteza and Sharghi, Mohammad and Narimani Ghourtlar, Samad and Török, Ákos and Vásárhelyi, Balázs},
	doi = {10.1038/s41598-023-28513-3},
	journal-iso = {SCI REP},
	journal = {SCIENTIFIC REPORTS},
	volume = {13},
	unique-id = {33581825},
	issn = {2045-2322},
	abstract = {Rocks deformed at low confining pressure are brittle, which means that after peak stress, the strength declines to a residual value established by sliding friction. The stress drop is the variation between peak and residual values. But no tension reduction takes place at high confining pressure. A proposed definition of the brittle-ductile transition is the transition pressure at which no loss in strength takes place. However, studies that consider information about the brittle-ductile transition, the criterion's range of applicability, how to determine mi, and how confining pressures affect m i 's values are scarce. This paper aims to investigate the link between brittle-ductile transition stress, uniaxial compressive strength and Hoek–Brown material constant ( m i ) for different kinds of rock. It is essential to accurately determine the brittle-ductile transition stress to derive reliable values for m i . To achieve this purpose, a large amount of data from the literature was chosen, regression analysis was carried out, and brittle-ductile transition stress (σ TR ) was determined based on the combination of Hoek–Brown failure criteria and the recently used brittle-ductile transition stress limit of Mogi. Moreover, new nonlinear correlations were established between uniaxial compressive strength and Hoek–Brown material constant ( m i ) for different igneous, sedimentary and metamorphic rock types. Regression analyses show that the determination coefficient between σ TR and UCS for gneiss is 0.9, sandstone is 0.8, and shale is 0.74. Similarly, the determination coefficient between σ TR and m i for gneiss is 0.88. The correlation between Hoek–Brown material constant ( m i ) and σ TR was not notable for sedimentary and metamorphic rocks, probably due to sedimentary rocks' stratification and metamorphic ones' foliation.},
	year = {2023},
	eissn = {2045-2322},
	orcid-numbers = {Török, Ákos/0000-0002-5394-4510; Vásárhelyi, Balázs/0000-0002-0568-1031}
}

@{MTMT:33571524,
	title = {Tunnel design across Zargos Main Fault - Iraq-Kurdistan Penjween Region},
	url = {https://m2.mtmt.hu/api/publication/33571524},
	author = {Deák, F. and Török, Ákos and Vásárhelyi, Balázs},
	booktitle = {Engineering problems in soft rocks},
	unique-id = {33571524},
	abstract = {After the economic boom in Iraq-Kurdistan the infrastructural reorganization began, based on the design of the highway and road network. The construction of the high number of tunnels is required because of the relief of the region thus the tracing of the roads can be better. Our Hungarian team was responsible for the verification of the Iranian-designed Penjween tunnel from Zagros Mountains (and Darbandikhan tunnel) in 2013. Our checking and consultant work helped the Client (Kurdistan Region Ministry of Construction and Housing-Sulaymaniyah) to prepare the Tender for the tunnel construction. The Tender process has stalled since the war began in the spring of 2014 in Iraq as well. The goal of this paper is to represent one part from the Hungarian team's checking work namely the geological site descriptions, drill core logging, laboratory results and the numerical modelling work which investigations were the background of final design of the Penjween tunnel. The paper introduces a methodology which provides an easy and in times a short manner for checking a tunnel design across an extended seismically active fault system and geologically very alterable rock masses. Due to the checking, we were spent a few days on the site around the tunnel trace. We have been carried out several engineering geological mapping on the outcrops found out in the close region. During our investigations based on our experiences, finally we were verified the required rock support by the designer. Hence there was short time for the checking work we have used analytical methods beside the simplified numerical models to cover the whole tunnel length. The designer has applied only 2D numerical modelling, therefore similarly we followed this approach, combined with analytical methods but the final results were analysed also by 3D numerical calculations (e.g. in case of the cross passages).},
	year = {2022},
	pages = {185-195},
	orcid-numbers = {Török, Ákos/0000-0002-5394-4510; Vásárhelyi, Balázs/0000-0002-0568-1031}
}