Balazs Vasarhelyi

Budapest University of Technology and Economics · Department of Engineering Geology and Geotechnics

Middle-Late Miocene clay layers, which occur in several places in Budapest (Hungary), contain varying amounts of sand, with predominance of sand in some cases. In this paper, the impact of this variability on the engineering properties of these clays is investigated, and comprehensive analysis is conducted on clay samples. The results of measuremen...

Citation: Gholipour, M.; Narimani, S.; Davarpanah, S.M.; Vásárhelyi, B.

Geomechanical properties such as uniaxial compressive strength (UCS) and modulus of elasticity (E) are essential for evaluating the mechanical behavior of rocks and crucial for rock engineering projects. Researchers frequently estimate these values indirectly because it is not always feasible to get high-quality core samples. Four machine learning...

A fúrómagok pontos elemzése elsődleges fontosságú a kőzetben és kőzeten történő tervezéshez. A fúrások elemzésére többféle módszer létezik, de a leginkább elfogadott és használt módszer a Rock Quality Designation (RQD) érték, amely 6 évtizede magminősítő érték. Az RQD érték a legtöbb kőzettest-osztályozás (például az RMR és a Q módszerek) egyik fon...

Az egytengelyű nyomószilárdsági vizsgálat (UCS) eredményei alapvető fontosságúak a Poisson-tényező értékének meghatározásához. A Nemzetközi Kőzetmechanikai Társaság (ISRM) javaslata szerint azonban a Poisson-tényező három alternatív módszerrel is meghatározható: a szekáns, az átlag és az érintő módszer segítségével. E módszerek alkalmazása eltérése...

Számos tanulmány a foglalkozik az ép kőzet rideg-képlékeny átmeneti feszültségnek meghatározásával. A természetben a kőzettestek számos tagoltságot (repedést, törést, stb.) tartalmaznak, így a kapott rideg-képlékeny átmeneti feszültség csak korlátozottan alkalmazható rájuk. A cikk célja a kőzettestek rideg-képlékeny átmeneti feszültségének meghatár...

Many studies focus on brittle-ductile transition stress in intact rocks; however, in real life, we deal with rock mass which contains many discontinuities. To fill this gap, this research focuses on the brittle-ductile transition stress of rock mass by considering the influence of different Geological Strength Index (GSI) values on the brittle-duct...

A középső-késő-miocén kori agyagrétegek, melyek Budapest, azon belül is inkább Pest területén is több helyen előfordulnak, változó mennyiségű homokot tartalmaznak, egyes esetekben a homok túlsúlya figyelhető meg. A cikkben feldolgozzuk azon mérési eredményeket, melyeknél a kötött talajok vizsgálata mellett (azaz folyási és sodrási határ, plasztikus...

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,...

Key geomechanical parameters utilized in rock engineering include Young's modulus and Poisson's ratio. Uniaxial compressive test results are essential in the evaluation of these values. This paper aims to study the process of changes of Poisson’s ratio and Young modulus for intact rock during loading from micro-crack initiation to failure stage. B...

A twin-tube motorway tunnel has been under construction near Sopron in Hungary. Geological inhomogeneity during the excavation required the redesigning of the schedule and reorganisation of the project. The geological overbreaks and weak, unstable tunnel faces caused minor stability problems that could be handled locally, but did not substantially...

The most common classification method of drill cores is the Rock Quality Designation (RQD) value, which indicates the percentage of rock cores longer than 10 cm in a given core section. This core logging procedure is the basic parameter in the most useful rock mass classification methods like Rock Mass Rate (RMR) and Rock Mass Quality (Q). It is al...

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, sedi...

ÖSSZEFOGLALÁS: A fúrómagok minősítésének legelterjedtebb módja az ún. RQD érték meghatározása, mely a 10 cm-nél hosszabb maganyagok %-os arányát mutatja be egy meghatározott hosszúságú fúrómag-szakaszon. Ez a minősítési eljárás alap-paraméter a legfontosabb kőzettest osztályozási eljárásban (RMR, Q), de segítségével a mind inkább teret nyerő Geológ...

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 char...

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,...

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 transiti...

The Poisson’s ratio of the intact rock material is one of the basic material constants for rock engineering calculations in and on rock environments. Recently, several relationships were developed to calculate of the Poisson’s ratio of the intact rock from different mechanical parameters (e.g., rigidity index, cohesion, internal friction angle). Th...

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-de...

The Geological Strength Index (GSI) is widely used for numerical modelling and rock engineering design in and on rock mass. It is one of the input parameters of the Hoek-Brown failure criteria and it can also be used for estimation of the deformation modulus and the Poisson's rate of the rock mass, among the other. The determination of this value i...

Classification of building materials, especially natural materials, is not straightforward, time-consuming and labour-intensive, as significantly more samples are required for a qualification process than for artificial materials. This investigation can be more complicate when the material behaviour (resistance) is examined against short time loadi...

Defining the practical and proper rock failure criteria plays the most significant role in analysis and design in rock mechanics and rock engineering. Up to now, several failure criterions have been proposed for brittle rocks. Among them, Hoek-Brown failure criterion has received much attention and applied among the others for brittle rocks. The go...

Slope stability analysis has received substantial attention in the scope of rock mechanics and rock engineering for many years. Various methods are available for analysing the stability of the vertical slope. The objective of this paper is to extend the proposed theoretical equation regarding tensile strength (t), Poisson's ratio () and bulk dens...

The freezing technique has been employed for a long time to strengthen the mechanical properties of intact rock and rock mass; however, it has not received as much attention as it deserves. This paper thoroughly reviews the effect of freezing on the essential mechanical properties, including uniaxial compressive strength, tensile strength, and Youn...

The mechanical properties of frozen rocks vary significantly from the properties of the same lithology under ambient temperature. The goal of this paper is to investigate these changes in the physical and mechanical properties of rocks due to saturation and freezing. Besides, the attention was paid on discovering new correlations between the mechan...

An accurate determination of Hoek–Brown constant m i is of great significance in the estimation of the failure criteria of brittle rock materials. So far, different approaches such as rigidity index method (R-index), uniaxial compressive strength-based method, and tensile strength-based method, and the combination of these two methods (combination...

Hazánk túlnyomó részét laza törmelékes üledékek, azaz valamilyen talajok borítják. Ezért a sziklarézsűk építése vagy a természetes sziklafalak ellenőrzése nem hétköznapi probléma, Magyarországon különleges feladatnak számít. Az állékonyság és a stabilitás számítása különösen fontos, hiszen az út- és vasútépítések melletti bevágások, nagymélységű mu...

A comprehensive understanding of geological, structural geological, hydrogeological and geotechnical features of the host rock are essential for the design and performance evaluation of surface and underground excavations. The Hungarian National Radioactive Waste Repository (NRWR) at Bátaapáti is constructed in a fractured granitic formation, and T...

Testing long-term properties of aggregates requires time consuming laboratory tests. Alternatively, mathematical models can also be used to describe the abrasion process of aggregates. The paper uses another approach it links long-term abrasion to rock mechanical properties to facilitate a quick assessment of long term behavior of aggregates. It ex...

Determining linear elastic stiffness parameters is a crucial aspect of ground characterization that enables subsequent numerical analyses using finite element, discrete element, and other procedures. Before estimating global settings for a rock mass relative to a proposed excavation such as a rock slope, tunnel or cavern, it is essential to underst...

According to its definition, Poisson's ratio is a measure of the Poisson effect, the phenomenon in which a material tends to expand in directions perpendicular to the direction of compression or, in other words, Poisson's ratio is the ratio of relative contraction to relative expansion. For the sake of simplicity, it is handled as a constant. Howev...

Determination of the mechanical behaviour of intact rock is one of the most important parts of any engineering projects in the field of rock mechanics. The most important mechanical parameters required to understand the quality of intact rock are Young’s modulus (E), Poisson’s ratio (ν), the strength of rock (σc) and the ratio of Young’s modulus to...

The determination of deformation parameters of rock material is an essential part of any design in rock mechanics. The goal of this paper is to show, that there is a relationship between static and dynamic modulus of elasticity (E), modulus of rigidity (G) and bulk modulus (K). For this purpose, different data on igneous, sedimentary and metamorphi...

Although Poisson’s ratio is one of the basic rock mechanical parameters, it is less investigated than the other parameters. It can be assumed, that this material constant depends on the rigidity of the rock, among the others. The goal of this research is to find a theoretical relationship between the rigidity of the intact rock and Poisson’s ratio....

of the long term data taking, related to one of the proposed next generation ground-based gravitational detector’s location is presented here. Results of seismic and infrasound noise, electromagnetic attenuation and cosmic muon radiation measurements are reported in the underground Matra Gravitational and Geophysical Laboratory near Gyöngyösoroszi,...

Although freezing has been used for decades for improving the strength parameters of rock masses around underground openings, there is limited research on the behavior of frozen materials. The objective of this paper is to investigate the relationship between different mechanical properties of highly porous limestone in case of dry, water saturated...

Understanding the quality of intact rock is one of the most important parts of any engineering projects in the field of rock mechanics. The expression of correlations between the engineering properties of intact rock has always been the scope of experimental research, driven by the need to depict the actual behaviour of rock and to calculate most a...

The Geological Strength Index (GSI) is one of the most important input parameter for rock engineering design in case of rock masses. Recently, several quantitative determinations of this value have been developed. These methods can be used for both rock cores and tunnel faces, as well. The paper presents different methods for calculating the GSI va...

Understanding the rock failure mechanism under dynamic loading is of high importance in rock engineering projects. It requires a model to address a coupling effect between plastic flow caused by sliding along micro-crack faces and damage evolution due to nucleation and growth of wing-cracks. The goal of this paper is to develop a self-consistent ba...

The Geological Strength Index (GSI) is one of the most important input parameter for rock engineering design in case of rock masses. Recently, several quantitative determinations of this value have been developed. These methods can be used for both rock cores and tunnel faces, as well. The paper presents different methods for calculating the GSI va...

Nearly 30 m high rock slope construction was necessary in soft rock condition during the construction of main road No. 21 in Hungary. Using rock mechanical laboratory test results, two different empirical rock classes (Slope Mass Rating-SMR and Q-slope) were applied to calculate the stability of the rock slope. For these calculations, the angles be...

With the intent of making data acquisition for fractal geometry-based discrete fracture network (DFN) modeling time-efficient and automatized, a new method was established. For the automation of data retrieval from the images of the studied surfaces, a series of image-processing operations and MATLAB algorithms have been developed. The method allow...

The mechanical properties of frozen rocks are very different from the properties of the same lithologies under ambient temperature. The goal of this paper is to describe the changes in the physical parameters of rocks caused by freezing. In addition, estimations are given on how these parameters are influenced by the intrinsic properties of rocks....

of the long term data taking, related to one of the proposed next generation ground-based gravitational detector's location is presented here. Results of seismic and infrasound noise, electromagnetic attenuation and cosmic muon radiation measurements are reported in the underground Matra Gravitational and Geophysical Laboratory near Gy\"ongy\"osoro...

The goal of this paper is to present the influence of the water saturation of the intact rock on different mechanical parameters , such as internal friction angle, cohesion, Hoek-Brown constant (m i). Analyzing the previously published results, it was found that due to water saturation both the uniaxial com-pressive strength and tensile strength de...

The Hoek-Brown (H-B) empirical failure envelope is widely used for calculating the mechanical behavior of the rock mass. An important input parameter of the H-B failure envelope is the Geological Strength Index (GSI), which was developed for the description of rock structure and block surface conditions. Using the GSI, the mechanical behavior of th...

Hydraulic fracturing results vary based on the physical and mechanical characteristics of intended area and state of stresses. This paper examines effects of homogeneity and non-homogeneity of rock samples and state of stresses on the outcomes of hydraulic fracturing in laboratory scale. Hence, 3 different types of cylindrical rock samples with dif...

Matra Gravitational and Geophysical Laboratory (MGGL) has been established near Gy\"ongy\"osoroszi, Hungary in 2015, in the cavern system of an unused ore mine. The Laboratory is located at 88~m below the surface, with the aim to measure and analyse the advantages of the underground installation of third generation gravitational wave detectors. Spe...

A kőzettestben/kőzettesten való tervezésnél, a kőzettest törési határgörbéjének meghatározása az ún. Hoek-Brown törési határgörbével történik. Ennek egyik bemenő paramétere a kőzettestet leíró, annak tagoltsági, szerkezeti állapotát figyelembe vevő Geológiai Szilárdsági Index (GSI), melynek értéke 0 és 100 között változhat. A cikk célja a Bátaapáti...

The knowledge of the main mechanical constants of a rock mass (such as strength, deformability and the Poisson’s ratio) is one of the most important for rock engineering design on or in rock mass. Until now, several empirical relationships were determined for calculating these material constants based on both the quality of the studied rock mass (i...

Matra Gravitational and Geophysical Laboratory (MGGL) has been established near Gy\"ongy\"osoroszi, Hungary in 2015, in the cavern system of an unused ore mine. The Laboratory is located at 88~m below the surface, with the aim to measure and analyse the advantages of the underground installation of third generation gravitational wave detectors. Spe...

Steep, and hardly accessible jointed rhyolite tuff cliff faces surround a Castle in NE-Hungary, at village of Sirok. The assessment of cliff stability required the recording of cliff geometry. Traditional surveying was not possible therefore cliff faces were 3D modelled by GNSS supported terrestrial laser scanner and UAV. The onsite engineering geo...

Elevated temperature causes changes in mechanical properties of rock, due to thermal effect and mineralogical transformations, which show great varieties for different lithologies. The present paper provides information on seven different sandstones. The studied predominantly quartz sandstones show different petrology from fine-grained to coarse-gr...

During the design process in rock engineering Hoek-Brown failure envelope is used for the determination of rock mass failure envelope mainly in brittle rocks. An important input parameter of the Hoek-Brown failure envelope is the Geological Strength Index (GSI), which varies between 0 and 100, and concentrates on the description of rock structure a...

A sókőzetek mechanikai tulajdonságainak vizsgálta gyakorlati szempontból is nagy jelentőségű, hiszen só dómokban van a világ szénhidrogén készletének egy jelentős része valamint a radioaktív hulladékok egyik potenciális befogadó kőzeteként is ismertek a sók. Először bemutatjuk a Parajdi sóbánya földtani és vízföldtani környezetét, Erdély geológiai...

Siroki várhegyet alkotó riolittufa állékonysági vizsgálatát mutatja be a cikk, kiemelve a térinformatika és a mérnökgeológia együttes alkalmazását. A sziklalejtő felmérésére az erősen tagolt domborzat miatt és a nehéz megközelíthetőség miatt GNSS támogatású földi lézerszkennelés és drónos légifényképezést alkalmaztunk. Az így kapott térinformatikai...

A cikk a lemezeknél használt ágyazási tényező közelítő számítási módszereit részletesen elemzi és összehasonlítja, hogy a bemenő talajparaméterek milyen hatással vannak az ágyazási tényező számértékére. A kapott eredményeket végeselemes programban tovább elemeztem, ipari padlók esetén, majd elvégeztem a közelítő képletek érzékenységvizsgálatát. Vég...

The Hoek–Brown empirical failure envelope is widely used for determining the strength of brittle intact rock and rock masses. One of the two independent parameters in the formula is the Hoek–Brown’s material constant (mi), which has several uncertainties, since it relies on a set of triaxial tests. The present paper introduces a new approach to det...

A Mátrai Gravitációs és Geofi zikai Laboratórium (MGGL) a rekultiváció alatt álló gyöngyösoroszi mélyművelésű bányában épült 2015-ben. A 88 m-rel a földfelszín alatt található létesítményben a harmadik generációs gravitációshullám-detektorok föld alatti telepítésének és folyamatos működésének lehetőségét vizsgáljuk. Szeizmikus, infrahang- és elektr...

Consistent application of “Design as you go”-principle is especially important during the design and construction of National Radioactive Waste Repository (Hungary). Due to the geological and hydrogeological constraint discovered within the previously licensed disposal zone during the construction, the area available for safe final disposal became...

Rideg kőzetek törési határgörbéjének pontos megadására ma már egyre inkább elterjedt a Hoek-Brown törési határfeltétel meghatározása, mind ép kőzet, mind kőzettest esetén. Az összefüggés felhasználásánál az egyik nehézséget az ún. Hoek-Brown paraméter felvétele jelenti: pontos kiméréséhez igen nagyszámú minta triaxiális vizsgálat szükséges, míg egy...

Épületek helyreállításánál, az építési kőanyag felhasználhatóságánál egyik probléma a tűzeset következtében bekövetkező változások megismerése, modellezése. Korábbi kutatások próbálták kimutatni, hogy egy adott kőzet esetén hőciklus hogyan változtatja meg a kőzet szilárdságát. Az ilyen jellegű mérési eredmények nem mutattak egyértelmű tendenciákat,...

A bimrock típusú csoportba olyan összetett, komplex kőzettípusokat sorolunk, melyekben a finomabb szemcséjű mátrix anyagba geotechnikailag jelentős blokkok, kavicsok találha-tók és a blokk-mátrix anyag között fellépő mechanikai feszültségek befolyásolják a kőzet szilárdságát. A bimrock típusú kőzetek nemzetközi szakirodalomba való bevezetése akkor...

A primer feszültségállapot főkomponens értékei alapvető fontosságúak a felszín alatti terek tervezéséhez. A nehézségi erő egy függőleges feszültséget eredményez (σv), amely a mély-ség felé haladva lineárisan növekszik. A kőzettestben fellépő vízszintes feszültség elméleti úton történő meghatározása már jóval nehezebb, így a horizontális síkban fell...