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Rock Quality Designation
Core recovery parameters describe the quality of core recovered from a borehole. Total core recovery Total core recovery (TCR) is the borehole core recovery percentage. TCR is defined as the quotient: :TCR = \left(\frac\right)\times 100 % :l_\mathrm = Sum of length of core pieces :l_\mathrm = Total length of core run Solid core recovery Solid core recovery (SCR) is the borehole core recovery percentage of solid, cylindrical, pieces of rock core. SCR is defined as the quotient: :SCR = \left(\frac\right)\times 100 % :l_ = Sum of length of solid, cylindrical, core pieces :l_ = Total length of core run Rock quality designation Rock-quality designation (RQD) is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. High-quality rock has an RQD of more than 75%, low quality of less than 50%. Rock quality designation (RQD) has several definitions. The most widely used definition was developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borehole
A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petroleum), or gases (such as natural gas). It may also be part of a geotechnical investigation, environmental site assessment, mineral exploration, temperature measurement, as a pilot hole for installing piers or underground utilities, for geothermal installations, or for underground storage of unwanted substances, e.g. in carbon capture and storage. Importance Engineers and environmental consultants use the term ''borehole'' to collectively describe all of the various types of holes drilled as part of a geotechnical investigation or environmental site assessment (a so-called Phase II ESA). This includes holes advanced to collect soil samples, water samples or rock cores, to advance ''in situ'' sampling equipment, or to install monitoring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percentage
In mathematics, a percentage (from la, per centum, "by a hundred") is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%", although the abbreviations "pct.", "pct" and sometimes "pc" are also used. A percentage is a dimensionless number (pure number); it has no unit of measurement. Examples For example, 45% (read as "forty-five per cent") is equal to the fraction , the ratio 45:55 (or 45:100 when comparing to the total rather than the other portion), or 0.45. Percentages are often used to express a proportionate part of a total. (Similarly, one can also express a number as a fraction of 1,000, using the term "per mille" or the symbol "".) Example 1 If 50% of the total number of students in the class are male, that means that 50 out of every 100 students are male. If there are 500 students, then 250 of them are male. Example 2 An increase of $0.15 on a price of $2.50 is an increase by a fraction of = 0.06. Expressed as a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Mass Rating System
Core recovery parameters describe the quality of core recovered from a borehole. Total core recovery Total core recovery (TCR) is the borehole core recovery percentage. TCR is defined as the quotient: :TCR = \left(\frac\right)\times 100 % :l_\mathrm = Sum of length of core pieces :l_\mathrm = Total length of core run Solid core recovery Solid core recovery (SCR) is the borehole core recovery percentage of solid, cylindrical, pieces of rock core. SCR is defined as the quotient: :SCR = \left(\frac\right)\times 100 % :l_ = Sum of length of solid, cylindrical, core pieces :l_ = Total length of core run Rock quality designation Rock-quality designation (RQD) is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. High-quality rock has an RQD of more than 75%, low quality of less than 50%. Rock quality designation (RQD) has several definitions. The most widely used definition was develope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q-system (geotechnical Engineering)
: ''For the linguistics formalism, see Q-systems.'' : ''For the genetic method, see Q-system (genetics).'' The Q-system for rock mass classification is developed by Barton, Lien, and Lunde. It expresses the quality of the rock mass in the so-called ''Q-value'', on which design are based and support recommendations for underground excavations. The Q-value is determined with ::Q=\frac \times \frac \times \frac The first term '' RQD'' ''(Rock Quality Designation)'' divided by ''Jn (joint set number)'' is related to the size of the intact rock blocks in the rock mass. The second term ''Jr (joint roughness number)'' divided by ''Ja (joint alteration number)'' is related to the shear strength along the discontinuity planes and the third term ''Jw (joint water parameter)'' divided by ''SRF (stress reduction factor)'' is related to the stress environment on the intact rock blocks and discontinuities around the underground excavation. A multiplication of the three terms results in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Mass Classification
Rock mass classification systems are used for various engineering design and stability analysis. These are based on empirical relations between rock mass parameters and engineering applications, such as tunnels, slopes, foundations, and excavatability. The first rock mass classification system in geotechnical engineering was proposed in 1946 for tunnels with steel set support. Design methods In engineering in rock, three design strategies can be distinguished: analytical, empirical, and numerical. Empirical, i.e. rock mass classification, methods are extensively used for feasibility and pre-design studies, and often also for the final design. Objectives The objectives of rock mass classifications are (after Bieniawski 1989): # Identify the most significant parameters influencing the behaviour of a rock mass. # Divide a particular rock mass formulation into groups of similar behaviour – rock mass classes of varying quality. # Provide a basis of understanding the characteristics o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Mass Rating
The rock mass rating (RMR) is a geomechanics, geomechanical classification system for Rock (geology), rocks, developed by Z. T. Bieniawski between 1972 and 1973. Since then it has undergone multiple modifications out of which, RMR89 is commonly used. Recently RMR14 has been proposed to improve the RMR performance by incorporating new experiences from tunnel practices. Continuous functions and a software "QuickRMR" for RMR89 and RMR14 have also been proposed by Kundu.Kundu, J., Sarkar, K., Singh, A.K., & Singh, T., 2020. Continuous functions and a computer application for rock mass rating. Int. J. Rock Mech. Min. Sci. 129. RMR combines the most significant geologic parameters of influence and represents them with one overall comprehensive index of rock mass quality, which is used for the design and construction of excavations in rock, such as tunnels, mines, slopes, and foundations. Definition The following six parameters are used to classify a rock mass using the RMR system #Uniax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q-system (Geotechnical Engineering)
: ''For the linguistics formalism, see Q-systems.'' : ''For the genetic method, see Q-system (genetics).'' The Q-system for rock mass classification is developed by Barton, Lien, and Lunde. It expresses the quality of the rock mass in the so-called ''Q-value'', on which design are based and support recommendations for underground excavations. The Q-value is determined with ::Q=\frac \times \frac \times \frac The first term '' RQD'' ''(Rock Quality Designation)'' divided by ''Jn (joint set number)'' is related to the size of the intact rock blocks in the rock mass. The second term ''Jr (joint roughness number)'' divided by ''Ja (joint alteration number)'' is related to the shear strength along the discontinuity planes and the third term ''Jw (joint water parameter)'' divided by ''SRF (stress reduction factor)'' is related to the stress environment on the intact rock blocks and discontinuities around the underground excavation. A multiplication of the three terms results in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISRM
The International Society for Rock Mechanics - ISRM was founded in Salzburg in 1962 as a result of the enlargement of the "Salzburger Kreis". Its foundation is mainly owed to Prof. Leopold Müller who acted as President of the Society until September 1966. The ISRM is a non-profit scientific association supported by the fees of the members and grants that do not impair its free action. In 2021 the Society had 6,800 members and 49 National Groups. The field of Rock Mechanics is taken to include all studies relative to the physical and mechanical behaviour of rocks and rock masses and the applications of this knowledge for the better understanding of geological processes and in the fields of Engineering. The main objectives and purposes of the Society are: * to encourage international collaboration and exchange of ideas and information between Rock Mechanics practitioners; * to encourage teaching, research, and advancement of knowledge in Rock Mechanics; * to promote high standards ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Springer Science+Business Media
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in Berlin, it expanded internationally in the 1960s, and through mergers in the 1990s and a sale to venture capitalists it fused with Wolters Kluwer and eventually became part of Springer Nature in 2015. Springer has major offices in Berlin, Heidelberg, Dordrecht, and New York City. History Julius Springer founded Springer-Verlag in Berlin in 1842 and his son Ferdinand Springer grew it from a small firm of 4 employees into Germany's then second largest academic publisher with 65 staff in 1872.Chronology ". Springer Science+Business Media. In 1964, Springer expanded its business internationally, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Mass Classification
Rock mass classification systems are used for various engineering design and stability analysis. These are based on empirical relations between rock mass parameters and engineering applications, such as tunnels, slopes, foundations, and excavatability. The first rock mass classification system in geotechnical engineering was proposed in 1946 for tunnels with steel set support. Design methods In engineering in rock, three design strategies can be distinguished: analytical, empirical, and numerical. Empirical, i.e. rock mass classification, methods are extensively used for feasibility and pre-design studies, and often also for the final design. Objectives The objectives of rock mass classifications are (after Bieniawski 1989): # Identify the most significant parameters influencing the behaviour of a rock mass. # Divide a particular rock mass formulation into groups of similar behaviour – rock mass classes of varying quality. # Provide a basis of understanding the characteristics o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Construction
Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management. Tunnel construction is a subset of underground construction. There are three basic types of tunnel construction in common use: * Cut-and-cover tunnel, constructed in a shallow trench and then covered over. * Bored tunnel, constructed in situ, without removing the ground above. They are usually of circular or horseshoe cross-section. Some concepts of underground mining apply. Modern techniques include Shotcrete used in the New Austrian tunnelling method, use of a tunnel boring machine (TBM) or tunnelling shield. But still tunnels are constructed which are secured with pit props and shoring and then are steine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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