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Calculation of the bond anchor bolt in elastoplastic medium
232A
Crushing and grinding 904282 Measurement of small grain size dimensions of crushed halite Straus, S H Rock Mechanics as a Guide for Elffcient Utilization o f Natural Resources: Proc 30th U.S. Symposium, l~lorgantown, 19-22 June 1989 P825-826. Publ Rotterdam: A A Balkema, 1989 Quantitative and qualitative microscopic examination of crushed, two dimensional halite particles was undertaken to determine the size of the third axis. Particles with and without significant amounts of polyhalite were further crushed in a mortar using vertical movement of the pestle. Photomicrographs showed both types of crystal tended towards a subangular and columnar shape, rather than classical cubic cleavage. This may be due to inclusions of other minerals.
Machine excavation See also: 904067
904283 Performance of helical drum with additional picks on the face side Krauze, K; Paraszczak, J Min Sci Technol VIO, NI, Jan 1990, P93-96 A Iongwall shearer is subject to force pushing it away from the coal face. This force is the sum of the lateral forces on all of the picks mounted on the drum, and is mainly dependent on the pick type and pick arrangement on the cutter drum. A helical drum with additional radial picks has been designed to minimise these radial forces. Test observations confirm the effectiveness of the design.
9O4285 Evolution of Australian bolting practice Tague, D; Aziz, N I; Smart, B G D g i n Engr Vl49, N342, March 1990, P336-342 Roofbolting was introduced into Australian coal mines in 1948/49. The practice of using shell type anchor bolts to supplement props and bars soon became widespread. Split wedge bolts and chemically grouted bolts came into general use in the 1960s and 1970s respectively. General rules for bolting are discussed, and typical applications to development roadways, face salvage, and major underground excavations such as coal storage caverns and shafts are illustrated.
904286 Practical rockbolting - evaluation and monitoring in the field Thompson, C D Proc 1st Regional Conferencefor Africa, Rock Mechanics in Africa, Swaziland, 3-4 November 1988 P297-303. Publ Marshalltown: SANGORM, 1988 When mechanised mining became widespread in South African coal mines, timber props were replaced as they limited machine manoevrability and ventilation. Expansion shell rockbolts were introduced, despite doubts about their ability in coal bearing strata. Field investigations into development of an efficient system using resin grouts and rebar rockbolts are described. Practical monitoring systems and test procedures have also been developed.
904287 Calculation of the bond anchor bolt in elastoplastic medium Zheng Yingren; Wang Cheng
Proc International Symposium on Underground Engineering, New Delhi, 14-17 April 1988 VI, P95-99. Publ Rotterdam: A A Balkema, 1988
Rock and Soil Reinforcement and Support See: 904151. 904402
An improved computational method is presented to describe behaviour of bolt/shotcrete support. The mass is divided into four concentric zones: shotcrete layer, plastic zone with bolts, plastic zone without bolts, and elastic zone. The action of the bolts in the rock mass is regarded as a volumetric force in an elastoplastic medium. Shear stress on the lateral surface of the bolt is expanded as a power series, whose exponents are found by considering relations between deformation of the rock mass and of the bolt.
Bolts and anchors See also: 904052
904284 Truss bolting at Ellington Combine Herron, T; Hunt, T Collier), Guard V238, NI, Jan 1990. P15-20
904288 Study on the effect of the vertical RC bolting on the unstable slope lwata, M; Mitarashi, Y; Masuda, M Proc International Geotechnical Symposium on Theory and Practice of Earth Reinforcement, Fukuoka Kyushu, 5-7 October 1988 P295-300. Publ Rotterdam: A A Balkema, 1988
Frequent roof falls were experienced during retreat Iongwalling in the Brass Thill seam of the undersea Eliington Combine colliery. Supplementary support using the roof truss, a tensioned cable between rock bolts to maintain the roof beam in compression, was employed. Principles, installation, design, and testing are described. Results of monitored loads and deformation, roadway closure and roof dilation are presented. Recommendations are made for future applications.
The use of reinforced concrete bolts, piles formed using 30ram diameter bolts in 100-120mm diameter holes filled with mortar, to support poor ground when tunnelling using the NATM is described. The technique may be used at shallow depth with beams used to spread the forces across the ground surface, when it supports by a suspension effect. The technique, design concepts and case studies are illustrated. Settlement and convergence are considered.
1990 Pergamon Press plc. Reproduction not permitted
Crushing and grinding 904282 Measurement of small grain size dimensions of crushed halite Straus, S H Rock Mechanics as a Guide for Elffcient Utilization o f Natural Resources: Proc 30th U.S. Symposium, l~lorgantown, 19-22 June 1989 P825-826. Publ Rotterdam: A A Balkema, 1989 Quantitative and qualitative microscopic examination of crushed, two dimensional halite particles was undertaken to determine the size of the third axis. Particles with and without significant amounts of polyhalite were further crushed in a mortar using vertical movement of the pestle. Photomicrographs showed both types of crystal tended towards a subangular and columnar shape, rather than classical cubic cleavage. This may be due to inclusions of other minerals.
Machine excavation See also: 904067
904283 Performance of helical drum with additional picks on the face side Krauze, K; Paraszczak, J Min Sci Technol VIO, NI, Jan 1990, P93-96 A Iongwall shearer is subject to force pushing it away from the coal face. This force is the sum of the lateral forces on all of the picks mounted on the drum, and is mainly dependent on the pick type and pick arrangement on the cutter drum. A helical drum with additional radial picks has been designed to minimise these radial forces. Test observations confirm the effectiveness of the design.
9O4285 Evolution of Australian bolting practice Tague, D; Aziz, N I; Smart, B G D g i n Engr Vl49, N342, March 1990, P336-342 Roofbolting was introduced into Australian coal mines in 1948/49. The practice of using shell type anchor bolts to supplement props and bars soon became widespread. Split wedge bolts and chemically grouted bolts came into general use in the 1960s and 1970s respectively. General rules for bolting are discussed, and typical applications to development roadways, face salvage, and major underground excavations such as coal storage caverns and shafts are illustrated.
904286 Practical rockbolting - evaluation and monitoring in the field Thompson, C D Proc 1st Regional Conferencefor Africa, Rock Mechanics in Africa, Swaziland, 3-4 November 1988 P297-303. Publ Marshalltown: SANGORM, 1988 When mechanised mining became widespread in South African coal mines, timber props were replaced as they limited machine manoevrability and ventilation. Expansion shell rockbolts were introduced, despite doubts about their ability in coal bearing strata. Field investigations into development of an efficient system using resin grouts and rebar rockbolts are described. Practical monitoring systems and test procedures have also been developed.
904287 Calculation of the bond anchor bolt in elastoplastic medium Zheng Yingren; Wang Cheng
Proc International Symposium on Underground Engineering, New Delhi, 14-17 April 1988 VI, P95-99. Publ Rotterdam: A A Balkema, 1988
Rock and Soil Reinforcement and Support See: 904151. 904402
An improved computational method is presented to describe behaviour of bolt/shotcrete support. The mass is divided into four concentric zones: shotcrete layer, plastic zone with bolts, plastic zone without bolts, and elastic zone. The action of the bolts in the rock mass is regarded as a volumetric force in an elastoplastic medium. Shear stress on the lateral surface of the bolt is expanded as a power series, whose exponents are found by considering relations between deformation of the rock mass and of the bolt.
Bolts and anchors See also: 904052
904284 Truss bolting at Ellington Combine Herron, T; Hunt, T Collier), Guard V238, NI, Jan 1990. P15-20
904288 Study on the effect of the vertical RC bolting on the unstable slope lwata, M; Mitarashi, Y; Masuda, M Proc International Geotechnical Symposium on Theory and Practice of Earth Reinforcement, Fukuoka Kyushu, 5-7 October 1988 P295-300. Publ Rotterdam: A A Balkema, 1988
Frequent roof falls were experienced during retreat Iongwalling in the Brass Thill seam of the undersea Eliington Combine colliery. Supplementary support using the roof truss, a tensioned cable between rock bolts to maintain the roof beam in compression, was employed. Principles, installation, design, and testing are described. Results of monitored loads and deformation, roadway closure and roof dilation are presented. Recommendations are made for future applications.
The use of reinforced concrete bolts, piles formed using 30ram diameter bolts in 100-120mm diameter holes filled with mortar, to support poor ground when tunnelling using the NATM is described. The technique may be used at shallow depth with beams used to spread the forces across the ground surface, when it supports by a suspension effect. The technique, design concepts and case studies are illustrated. Settlement and convergence are considered.
1990 Pergamon Press plc. Reproduction not permitted