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Importance of discontinuities in rock mass engineering: genesis, characteristics and application
ROCK BREAKAGE:FRACTURE
Rock block analysis 957232 Bedeutung yon Trennflachen im Feisbau: Genese, Charakterist/k und Anwendung (Importauee of discontinuities in rock mass engineering: genesis, characteristics and application) J. Michael, Felsbau, 12(6), 1994, pp 382-386. The pattern of discontinuities of the Suddcutsche Grossscholle is very complex and developed during several tectonic events. Its kinematic and dynamic solution has made great progress through the analysis of geophysical, mathematical and geotechnical data in association with the interpretation of tunnel excavation analysis, accompanied by deformation measurement and geological rock descriptions. (from English summary) 957233 Genmuehanical modelling of jointed rock H. S. W. Kulatilake & G. Swoboda, Felsbau, 12(6), 1994, pp 387-394. A good understanding of the mechanical properties of discontinuous (jointed) rock masses is vital to arrive at safe and economical designs for geoteclmical structures in and on rock masses. Geotechnical structures in jointed rock are encountered in civil, mining and petroleum engineering disciplines. The presence of discontinuities strongly affects the mechanical behaviour of rock masses. The following types of problems need to be addressed: 1) effect of major discontinuities on deformation and stability of rock masses, 2) estimation of equivalent mechanical behaviour of rock masses which contain intact rock and minor discontinuities, and 3) procedures to perform stress, deformation and stability analysis of large rock masses which contain intact rock and both major and minor discontinuities. This paper discusses briefly the procedures available, as well as some new
335A
experimental frisbec deposit gauge. X-ray diffraction was used to characterize the dust on the basis of mineralogy. Scanning electron microscopy was used to examine particle size and shape and an energy dispersive X-ray analysis system was used to locate coal particles. This new dust data technology already shows considerable potential for use in nuisance complaints, planning applications, site ficence renewals and for the implementation of future European environmental protection legislation. (from Authors)
957236 Russian mining technique avoids blasting ANON, Coal International, 243(3), 1995, p 110. A recent Symposium on Sustainable Development of Opencast Coal Mining Regions, made reference to new Russian technique for preparing coal and hard overburden. It entails no preliminary blasting and essentially consists of treating the rock or coal with special aquenus solutions of surfactants and salts that are adsorbed at the inner pore surface of the rock, lowering its surface energy and altering its physical and mechanical properties. Testing has revealed that combined physical and chemical loosening of the solid reduces the energy intensity of extraction by 20-35%, increases excavator productivity by up to 30%, and reduces the need to move mining machinery around by 40%. The abrasiveness of the rock and coal is also reduced by 30-40%. Using a combination of the new method and blasting to prepare hard rock for extraction reduces explosives consumption by 25-30% and cuts the amount of drilling required by up to 25%. (from Author)
Rock fracture under dynamic stress
techniques for tackling these problems. (from Authors) 957234 Msthematisehe ModelHerung yon gekluftetem Feis (Mathematleal medelUng of jointed rock) H. Konietzky, R. Hart & D. Billaux, Felsbau, 12(6), 1994, pp 395-400. The Distinct Element Method (DEM) is presented as an adequate numerical modelling tool for jointed rock. The DEM allows the 2- and 3-dimensional modelling of hydraulic-thermal-mechanical coupled processes, including dynamic processes. In this connection all possible kinematic contracts and movements are automatically detected and performed. The power of the DEM for the solution of problems in civil engineering problems and in geosciences is illustrated by project examples. (from English summary)
ROCK BREAKAGE AND EXCAVATION General 957235 Environmental dust analysis in opencast mining areas J. Merefield & 6 others, in: European coal geology, ed M.K.G. Whateley & D.A. Spears, (Geological Society of London; Special Publication, 82), 1995, pp 181-188. An atmospheric dust database has been set up for the western end of the South Wales Coalfield. This, the first of its kind in the UK, comprises dust data from British Standard 1747 four-way directional gauges, a window ledge sampler and an
957237 A marriage of two techaolegies B. P. Micke, J. D. Watson & C. Young III, Tunnels & Tunnelling, 27(3), 1995, pp 57-60. This article describes in detail penetrating cone fracture (PCF) technology for hard rock excavation. Developed by Sunburst Excavation, the technique uses a gas injector which bums solid propellants to generate a high pressure pulse to induce the PCF type of rock breakage. The rock fails in tension at a lower stress level and with greater energy efficiency than other methods. A continuous excavation system has been developed. Other major features are: low velocity flyrock, controlled size distribution of broken rock, minimised damage to remaining rock, and low level ground movements. Performance characteristics and introduction of the technology in the mining and construction industries are discussed. (J.M.McLaughlin)
957238 Pressure for change A. Oliver, New Civil Engineer (NCE), 1121, 1995, pp 12-13. The background to the consultative draft proposals for new regulations for tunnelling in compressed air recently pubfished by the Health & Safety Executive is outlined. The draft includes revised guidelines on the use of compremxi air for tunnelling. The new regulations will also require a clear definition for the role of people in charge of tunnelling contracts. Other requirements included in the draft are outlined. (P.M.Taylor)
Rock block analysis 957232 Bedeutung yon Trennflachen im Feisbau: Genese, Charakterist/k und Anwendung (Importauee of discontinuities in rock mass engineering: genesis, characteristics and application) J. Michael, Felsbau, 12(6), 1994, pp 382-386. The pattern of discontinuities of the Suddcutsche Grossscholle is very complex and developed during several tectonic events. Its kinematic and dynamic solution has made great progress through the analysis of geophysical, mathematical and geotechnical data in association with the interpretation of tunnel excavation analysis, accompanied by deformation measurement and geological rock descriptions. (from English summary) 957233 Genmuehanical modelling of jointed rock H. S. W. Kulatilake & G. Swoboda, Felsbau, 12(6), 1994, pp 387-394. A good understanding of the mechanical properties of discontinuous (jointed) rock masses is vital to arrive at safe and economical designs for geoteclmical structures in and on rock masses. Geotechnical structures in jointed rock are encountered in civil, mining and petroleum engineering disciplines. The presence of discontinuities strongly affects the mechanical behaviour of rock masses. The following types of problems need to be addressed: 1) effect of major discontinuities on deformation and stability of rock masses, 2) estimation of equivalent mechanical behaviour of rock masses which contain intact rock and minor discontinuities, and 3) procedures to perform stress, deformation and stability analysis of large rock masses which contain intact rock and both major and minor discontinuities. This paper discusses briefly the procedures available, as well as some new
335A
experimental frisbec deposit gauge. X-ray diffraction was used to characterize the dust on the basis of mineralogy. Scanning electron microscopy was used to examine particle size and shape and an energy dispersive X-ray analysis system was used to locate coal particles. This new dust data technology already shows considerable potential for use in nuisance complaints, planning applications, site ficence renewals and for the implementation of future European environmental protection legislation. (from Authors)
957236 Russian mining technique avoids blasting ANON, Coal International, 243(3), 1995, p 110. A recent Symposium on Sustainable Development of Opencast Coal Mining Regions, made reference to new Russian technique for preparing coal and hard overburden. It entails no preliminary blasting and essentially consists of treating the rock or coal with special aquenus solutions of surfactants and salts that are adsorbed at the inner pore surface of the rock, lowering its surface energy and altering its physical and mechanical properties. Testing has revealed that combined physical and chemical loosening of the solid reduces the energy intensity of extraction by 20-35%, increases excavator productivity by up to 30%, and reduces the need to move mining machinery around by 40%. The abrasiveness of the rock and coal is also reduced by 30-40%. Using a combination of the new method and blasting to prepare hard rock for extraction reduces explosives consumption by 25-30% and cuts the amount of drilling required by up to 25%. (from Author)
Rock fracture under dynamic stress
techniques for tackling these problems. (from Authors) 957234 Msthematisehe ModelHerung yon gekluftetem Feis (Mathematleal medelUng of jointed rock) H. Konietzky, R. Hart & D. Billaux, Felsbau, 12(6), 1994, pp 395-400. The Distinct Element Method (DEM) is presented as an adequate numerical modelling tool for jointed rock. The DEM allows the 2- and 3-dimensional modelling of hydraulic-thermal-mechanical coupled processes, including dynamic processes. In this connection all possible kinematic contracts and movements are automatically detected and performed. The power of the DEM for the solution of problems in civil engineering problems and in geosciences is illustrated by project examples. (from English summary)
ROCK BREAKAGE AND EXCAVATION General 957235 Environmental dust analysis in opencast mining areas J. Merefield & 6 others, in: European coal geology, ed M.K.G. Whateley & D.A. Spears, (Geological Society of London; Special Publication, 82), 1995, pp 181-188. An atmospheric dust database has been set up for the western end of the South Wales Coalfield. This, the first of its kind in the UK, comprises dust data from British Standard 1747 four-way directional gauges, a window ledge sampler and an
957237 A marriage of two techaolegies B. P. Micke, J. D. Watson & C. Young III, Tunnels & Tunnelling, 27(3), 1995, pp 57-60. This article describes in detail penetrating cone fracture (PCF) technology for hard rock excavation. Developed by Sunburst Excavation, the technique uses a gas injector which bums solid propellants to generate a high pressure pulse to induce the PCF type of rock breakage. The rock fails in tension at a lower stress level and with greater energy efficiency than other methods. A continuous excavation system has been developed. Other major features are: low velocity flyrock, controlled size distribution of broken rock, minimised damage to remaining rock, and low level ground movements. Performance characteristics and introduction of the technology in the mining and construction industries are discussed. (J.M.McLaughlin)
957238 Pressure for change A. Oliver, New Civil Engineer (NCE), 1121, 1995, pp 12-13. The background to the consultative draft proposals for new regulations for tunnelling in compressed air recently pubfished by the Health & Safety Executive is outlined. The draft includes revised guidelines on the use of compremxi air for tunnelling. The new regulations will also require a clear definition for the role of people in charge of tunnelling contracts. Other requirements included in the draft are outlined. (P.M.Taylor)