Study of Rock Mass Rating (RMR) and Geological Strength Index (GSI) Correlations in Granite, Siltstone, Sandstone and Quartzite Rock Masses

Somodi, Gábor; Bar, Neil; Kovács, László; Arrieta, Marco; Török, Ákos; Vásárhelyi, Balázs

doi:10.3390/app11083351

Cited by 14 publications

(10 citation statements)

References 31 publications

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“…However, the evaluation of discontinuities changes significantly in both methods: RMR considers the spacing (the greater the spacing, the greater the RMR), while the Q index evaluates the number of families (the greater the number of families, the lower the Q index, regardless of their spacing). According to Somodi et al [58], using more than one geomechanical evaluation methodology favours understanding the behaviour of rock masses.…”

Section: Discussionmentioning

confidence: 99%

“…The most widely used systems for estimating stability conditions and support measures for many underground constructions are rock mass rating (RMR) [53], Q [54], geological strength index (GSI) [55], mining rock mass rating (MRMR) [56], and rock mass index (RMi) [57]. Although there are several classifications of rock masses, using more than one classification is highly recommended to obtain a comprehensive understanding of the host rock and predict soil behaviour [58].…”

Section: Introductionmentioning

confidence: 99%

“…Geomechanical classification systems generate debate among geoscientists because they present limitations owing to subjective valuation uncertainties [59]. However, geome-chanical classification is the only practical basis for the design of projects related to complex underground structures [58]. The quality of rock mass materials in underground excavations cannot be measured exclusively by strength tests but instead requires methodologies with holistic approaches that consider various geological parameters [57].…”

Section: Introductionmentioning

confidence: 99%

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Application of Geomechanical Classification Systems in a Tourist Mine for Establishing Strategies within 3G’s Model

Aguilar

Jaya-Montalvo

Loor-Oporto³

et al. 2023

Heritage

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Stability problems in rock masses are one of the main causes of subsidence events in underground mining areas. Zaruma, in the South of Ecuador, is characterised by mineral wealth, in which 65% of the population depends directly on artisanal mining activity. However, mineral extraction, without technical considerations and in many cases illegal, has negatively impacted the stability of tunnels generated under the city’s urban area, reporting subsidence events in recent years. The aim of this study is to geomechanically characterise the main gallery of the tourist mine “El Sexmo” using two classic methods of geomechanical classification for the configuration of a model that complies with the 3G’s (geotourism, geoconservation, and geoeducation) and supports the culture of sustainability in all areas of the sector. The methodology consists of (i) a field study design, (ii) a geological–geomechanical survey of the rock mass of a tourist mine using rock mass rating (RMR) and the Q-Barton index, and (iii) establishing a 3G’s model for sustainable development. The results reveal that 100% of the rock mass of the tourist mine presents a rock quality classified as “Fair” (class III) by the RMR method, while, via the Q-Barton method, 92.9% of the rock mass obtains a “Poor” rating, except for station S05, rated “Very Poor”. Furthermore, the study proposes additional support measures for three specific stations based on Q-Barton assessments, including fibre-reinforced sprayed concrete and bolting and reinforced ribs of sprayed concrete, considering that the mine is more than 500 years old and maintains geological features for geoeducation in geotechnical mining. Technical and social problems demand an innovative strategy, which, in this work, focuses on the 3G’s model based on the quintuple innovation helix to develop sustainable underground geotourism.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Application of Geomechanical Classification Systems in a Tourist Mine for Establishing Strategies within 3G’s Model

Aguilar

Jaya-Montalvo

Loor-Oporto³

et al. 2023

Heritage

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“…The value of the m i for soft rocks is approximately between 2 and 14, according to the suggested table by [6]. The Geological Strength Index (GSI) is widely used for estimating the strength reduction from an intact rock to a rock mass [7], and there are different ways to determine its value [8]; the determination of GSI is not easy and not exact [9].…”

Section: Introductionmentioning

confidence: 99%

The Effect of GSI and mi on the Stability of 3D Twin Tunnel in Limestone

Zenah,

Görög

2024

Period. Polytech. Civil Eng.

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The Generalised Hoek-Brown (GHB) failure criterion is one of the most used criteria to study the behaviour of the rocks; affected parameters of the Hoek-Brown equation are Geological Strength Index (GSI), intact rock constant (mi), and Disturbance factor (D). GSI is one of the rock classification systems used to evaluate jointed rocks. In light of this equation, this paper studies the stability of unsupported twin tunnels in a weak rock by changing the mentioned parameters (GSI, mi) to find the relation between the stability and these parameters under different distances between the centres of the tunnels (L). The tunnels have a circular cross-section with a diameter (B), and they have been modelled in three dimensions using Rocscience software package (RS3). The results showed that the stability of the tunnels, which was represented by the strength reduction factor (SRF), increased as a result of increasing L/B or GSI in the studied range; for mi , the modelling results showed that the SRF value increased while mi value was increased.

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“…Geomechanical parameters of rock mass classification systems should reflect actual ground conditions and take into account their impact on the stability of the underground mining excavation (Somodi et al, 2021). Over the last five decades, several rock mass classification systems have become very widely used in underground mining works to estimate the geo-mechanical characteristics of rock masses in excavated areas in order to establish the appropriate support system (Soufi et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Geomechanical characterization of rock mass rating and numerical modeling for underground mining excavation design

Kimour¹,

Boukelloul²,

Hafsaoui³

et al. 2023

Journ. Geol., Geogr., and Geoec..

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The objective of the study is the geomechanical characterization of the rock mass rating RMR system and numerical modeling for mining underground excavation design of the Djebel El Ouahch tunnel, in Constantine (Algeria).The geological and geotechnical character- ization of the rock mass is important for the design of underground mining excavations. In this article, we present the results of the RMR characterization of the rock mass and the numerical modeling by the finite element method (FEM), under the conditions of the Djebel El Ouahch tunnel, Constantine (Algeria).The RMR system is a useful tool for characterization of the rock mass quality and establishing the appropriate support system. For poor rock (Class IV), the excavation should be top heading and bench 1.0 m – 1.5 m advance in top heading. Support should be installed concurrently with excavation, 10 m from face. Rock bolting should be systematic with 4 m – 5 m long, spaced 1.5 m – 1.5 m in the crown and walls with wire mesh, Shotcrete of 100 m -150 mm in the crown and 100 mm in sides. The steel sets should be light to medium ribs spaced 1.5 m only when required. The rock mass consists of generally poor rocks with average stand- up time of 10 hours for 2.5m span with mass cohesion ranges between 100 kPa – 200 kPa and rock mass friction angle ranges from 15° to 35°. The FEM project due to its precision calculates the safety factor and evaluates the principal deformations and displacements of the rocks mass .The originality of this work lies in the use of two different approaches , the RMR system and numerical method (FEM) for analyzing the quality and evaluation of the deformations and displace- ments of rock mass .This method has become a very common practice in underground mining excavation design.This study illustrates that the results obtained by RMR of the argillite rock mass in the case is 28.00 ,ranging from 21.0 to 40.0 classified as Class IV (Poor Rock), while the results of FEM reveal that in accordance with the poor quality of the rocks, large deformations and displacements were observed around the underground mining excavation, which can be at the origin of the ruptures. The value of the safety factor of the order of 0.95 to 1.24 shows the instability of the excavation, and the appearance of very considerable hazard zones in the argillite layer.

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Study of Rock Mass Rating (RMR) and Geological Strength Index (GSI) Correlations in Granite, Siltstone, Sandstone and Quartzite Rock Masses

Cited by 14 publications

References 31 publications

Application of Geomechanical Classification Systems in a Tourist Mine for Establishing Strategies within 3G’s Model

Application of Geomechanical Classification Systems in a Tourist Mine for Establishing Strategies within 3G’s Model

The Effect of GSI and mi on the Stability of 3D Twin Tunnel in Limestone

Geomechanical characterization of rock mass rating and numerical modeling for underground mining excavation design

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