A New Rock Mass Quality Rating System: Rock Mass Quality Rating (RMQR) and Its Application to the Estimation of Geomechanical Characteristics of Rock Masses

RESUMENDesde el siglo XX se han propuesto varios sistemas de clasificación del macizo rocoso. Entre ellos destacan el sistema RMR de Bieniawski y el sistema Q de Barton, que son las clasificaciones más empleadas en todo el mundo. Se han propuesto numerosas relaciones entre ambos índices, que normalmente tienen gran dispersión de datos. Sin embargo, se ha observado que las correlaciones establecidas para litologías específicas son más precisas. El objetivo de este artículo es proponer una correlación entre el índice RMR y Q para formaciones sedimentarias de grano fino, habituales en la zona de Bilbao (España), mediante los datos recopilados in situ durante la excavación del túnel Etxebarri-Casco Viejo de la línea 3 del Ferrocarril Metropolitano de Bilbao. La ecuación obtenida muestra un alto grado de correlación y se ha propuesto una relación única entre los dos sistemas de clasificación, que no depende de la variable independiente escogida.Palabras clave: índice RMR; índice Q; clasificación del macizo rocoso; excavación de túneles; geomecánica; roca sedimentaria. ABSTRACT INTRODUCCIÓNAl contrario que otros materiales empleados habitualmente en ingeniería, como el hormigón o el acero, que poseen caracterís-ticas controladas, la roca in situ es uno de los materiales más complejos a los que se enfrentan los ingenieros civiles, geólo-go-geotécnicos o de minas. El macizo rocoso puede ser definido como el material no homogéneo formado por fragmentos y bloques de roca de distinto tamaño, intacta o alterada, con sus defectos, separados por una serie de discontinuidades, como juntas, fallas, planos estratificación, etc., que además varía su composición en el espacio y en el tiempo (1) (2) (3). En consecuencia, es necesario considerar las propiedades ingenieriles de la roca intacta y del macizo rocoso. Además, excepto en el caso de que existan alternativas para el proyecto, lo cual es muy poco frecuente, los ingenieros responsables deben hacer frente a este material variable, con un comportamiento complejo, que depende de las condiciones de carga.Por consiguiente, las clasificaciones del macizo rocoso han sido necesarias para la comunicación del conocimiento y experiencia adquirida por los ingenieros y geólogos en lugares con diversas condiciones geológicas y con diferentes soluciones de sostenimiento y, de esta manera, poder ser útil en nuevos proyectos (4).Mientras que únicamente un sistema de clasificación de suelos, propuesto por Casagrande, es empleado ampliamente en la actualidad para los suelos; numerosos sistemas de clasificación cualitativa y cuantitativa del macizo rocoso han aparecido desde el inicio del siglo XX. La Tabla 1 muestra un resumen de los sistemas más empleados a lo largo del mundo, indicándose el autor, cuándo fue desarrollado y el campo de aplicación del sistema propuesto.Los sistemas de clasificación del macizo rocoso se basan principalmente en un enfoque empírico y fueron desarrollados como una herramienta de diseño sistemática en la ingeniería civil y minera. Tienen por objetivo ordenar y sis...

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“…Una vez verificada la normalidad de los datos, se utiliza el enfoque probabilístico propuesto por Kasier et al (25), mediante la ecuación [21]:…”

Section: Metodología Aplicadaunclassified

Correlación entre el índice RMR de Bieniawski y el índice Q de Barton en formaciones sedimentarias de grano fino

2017

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“…Different rock mass classification schemes relied on the different engineering geological characteristics of the rock masses that were obtained as an outcome of the experience from variety of civil engineering case histories. Rock mass classification systems of Terzaghi (1946) and Stini (1950) can be referred as the earliest but base of the modern rock mass classifications (Aydan et al, 2014). Terzaghi (1946) explained the rock mass descriptions depending on the engineering geology information for the design of tunnel support.…”

Section: Development Of Rock Mechanics and Rock Mass Classification Smentioning

confidence: 99%

İlk Çağlardan Günümüze Yeraltı Yapıları, Kaya Yapıları ve Kaya Mekaniği

Akış¹,

Satıcı²

2017

Jeoloji Mühendisliği Dergisi

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Usage of underground space is an old habit for human beings since ancient era. Our ancestors have used caves as a shelter for protection from the wild life and nature, and they excavated caves to extract valuable minerals. They also used them as sanctuaries, tombs or for storage of goods. In addition, they built tunnels to be used as assault systems or to underpass fortifications during ancient warfare. Later on, tunnels were driven to supply water to the towns or to protect the towns from floods. They also built them for communication purposes. Though not knowing the exact time when they were first used, natural underground structures which have several interconnections were also built for underground dwelling purposes through the human history. In the following centuries, due to the need of transportation facilities, transportation tunnels were constructed where new excavation techniques were also used. Navigation canal tunnels, railway tunnels and road tunnels were constructed during that period. All these structures were mostly excavated in rocks. The first excavations were performed manually. Later on, fire technique had been used to excavate more easily. This was followed by the methods in which gunpowder, explosives and tunneling machinery were used. By some means or other, ancient civilizations had used fundamental principles of rock mechanics and applied these principles in the construction of the underground structures. Principles of rock mechanics are the sine qua non for all of these structures and facilities. In this review paper, the history and evaluation of rock mechanics will be given briefly and some examples of historical and monumental underground and rock structures will be presented. Keywords

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“…the deformation modulus may be estimated from the uniaxial compressive strength (see also [3,19,44]:…”

Section: Connection Between the Deformation Modulus And The Strength mentioning

confidence: 99%

Empirical methods of calculating the mechanical parameters of the rock mass

Vásárhelyi

Kovács²

2016

Period. Polytech. Civil Eng.

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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 (ie. RMR or GSI values) IntroductionLarge scale rock mass characterization introduces material parameters related to mechanical properties. The most important properties are the deformation modulus; the unconfined strength and the Poisson's ratio value of the rock mass in interest. These material parameters are frequently related to laboratory data characteristics of intact rock samples and to the classical rock mass classification systems (e.g. RQD, Q, RMR or GSI). These rock mass quality measures quantify the relation between the rock mass and the intact rock.The established empirical relations between the mechanical parameters of rock masses (unconfined compressive strength, deformation modulus) and the rock mass classification systems (RMR or GSI values) show exponential increasing deformation modulus and compressive strength with the increasing quality of the rock mass.The paper summarizes the observed correlations published between the mechanical properties of rock masses and one of the rock mass classification systems. It was found, that the deformation modulus and the strength of a rock mass data may reflect a simple exponential relationship of the observed quantities. According to analysis of different proposed equations a new formula is suggested and the modification ratio (i.e. ratio of the deformation modulus and the strength of rock mass) is also determined.However, it is important to note, that there are huge differences between the published date and the empirical formulas. The reason for this variance is the difference in situ testing methods, that may give different values of mechanical parameters even for the same rock mass. According to Bieniawski [1], even a single testing method, such as flat jack test, can lead to a widely scattering results even where the rock mass is very uniform. The other reason for the discrepancy in the different calculation methods is the directional effect. Most rock masses are anisotropic and do not have single deformation modulus [2].There is no mechanical (physical) interpretation of the above empirical equations but these were analysed by e.g. [3]. Recently, Ván and Vásárhelyi [4] suggested a damage mechanical approach to analyse them. In this paper their method will be also presented.

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A New Rock Mass Quality Rating System: Rock Mass Quality Rating (RMQR) and Its Application to the Estimation of Geomechanical Characteristics of Rock Masses

Cited by 88 publications

References 24 publications

Correlación entre el índice <em>RMR</em> de Bieniawski y el índice <em>Q</em> de Barton en formaciones sedimentarias de grano fino

Correlación entre el índice <em>RMR</em> de Bieniawski y el índice <em>Q</em> de Barton en formaciones sedimentarias de grano fino

İlk Çağlardan Günümüze Yeraltı Yapıları, Kaya Yapıları ve Kaya Mekaniği

Empirical methods of calculating the mechanical parameters of the rock mass

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