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Failure modes and pillar behaviour in the Zinkgruvan mine
200A elastic and plastic regions. Numerical examples are presented which illustrate the extent of the plastic zone around rectangular and single and multiple parallel circular openings. 933468 Analysis of borehole stability using discrete element models Thallak, S; Rothenburg, L; Dusseault, M Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16-20 September 1991 V1, P813-818. Publ Rotterdam: A A Balkema, 1991
The DEM is used to examine the mechanics of deformation, yield, and load transfer around a borehole in a dense granular medium, simulated by an array of 2D idealised discs. Both hydrostatic and non-hydrostatic stress fields are considered. Annular dilation, nonlinear behaviour, shear zone generation, and the development of borehole breakout can be reasonably simulated. Stress distributions computed using the DEM are compared to those from conventional analytical solutions. 933469 Mechanical effects of pressure and temperature variation on annular cement in oil wells Charara, I; Minh, D N Proc 33rd US Symposium on Rock Mechanics, Santa Fe, 3-5 June 1992 P429-437. Publ Rotterdam: A A Balkema, 1992
The possibility of damage to the cement annulus in a cased oil or gas well as a result of thermal loading due to injection of hot steam or cool mud or mechanical loading as a result of change in internal casing pressure is analysed. The cement is considered linear viscoelastic, the rock elastic or viscoelastic, the steel casing elastic. Parametric study is made to quantify how close the stress state in the cement gets to its failure criterion. Significant extra stresses are found at the cement-casing interface, especially for the case of simultaneous cooling and pressure variation.
Underground excavation failure mechanisms 933470 Failure modes and pillar belmviour in the Zinkgrnvan mine Sjoberg, J Proc 33rd US Symposium on Rock Mechanics, Santa Fe, 3-5 June 1992 P491-500. Publ Rotterdam: A A Balkema, 1992 A tabular, steeply dipping orebody is mined at a distance of 1800m along the strike at the Zinkgruvan mine, Sweden. Mining has now reached the 840m level. Instability problems in stope roofs and sill pillars have been met. Failure modes and local geology have been studied and correlated. Numerical modelling using the UDEC and FLAC codes can reproduce observed modes of failure and MINSIM-D can predict onset of failure. Simple to use stress level criteria for different modes of failure have been developed. The need to identify geological conditions in planning for this mine is emphasised.
Tunnels 933471 Tunnel __detagnand comtrnction Crighton, G S; Biggart, A E; Norie, E H lust Ci~ E q r s Proc Special Issue: The Channel Tunnel P1842, 1992
The design concepts and planning and construction programs for the Channel Tunnel are outlined. The main elements of the scheme are described and development and organisation of the
planning program, site investigation, preconstructional organisation, main features of the NATM tunnels, bored tunnels, and major underground structures, and fitting-out are discussed. 933472 Machine-driven tunnels Chapman, P J; Wrightam, V H; Ince, G; Lewis, R P lust Civ Eugrs Proc Special Issue: The Channel Tunnel P5586, 1992 One major aspect of UK underground work for the Channel Tunnel was 84kin of TBM driven tunnels, which required six machines, each specifically designed and constructed for continuous high-speed working. Factors which were considered in selecting this construction method are outlined. The designs of the TBMs for the pilot tunnel, land running tunnels, and marine running tunnels and their ancillary equipment are illustrated. Tunnelling experiences and the performance achieved are discussed. 933473 Three-dimensional modelllm~ of junctions at the Channel Tunnel Project. Technical note on practical applications Potter, R Int J Num Anal MetA Geomeeli F16, N9, Sept 1992, P683695 The underground marshalling area for the Channel Tunnel project required numerous connections between caverns and tunnels of various sections. Three dimensional finite element analysis of a representative junction was carried out and the impact of the results on engineering practice, in particular design of the final lining, assessed. Construction was according to NATM principles. The importance of combining the FE modelling data with engineering judgement and geological information for design decisions is noted. 933474 Rigorously determined support characteristics and support design method for tunnels subject to squeezing conditions Kirsten, H A D; Bartlett, P J J S Aft lust Min Metall V92, N7, July 1992, P195-214 A rigorous design system for support of tunnels at the Premier Mine in South Africa is required to validate and augment the current empirical NATM-Q system. A 2D numerical simulation based on the finite difference code FLAC is used. Mine layout, mining sequences, and field stresses are outlined. 25 support configurations have been evaluated for a range of tunnel sizes and shapes. Loads on the rock reinforcement around the tunnel have been analysed. It is seen that the empirical design may significantly underestimate support requirements in squeezing ground. 933475 Simulation of rock-liner interaction for tunnels in isotropic and anisotropic rock masses Pelli, F; Kaiser, P; Morgenstern, N R Proc 7th ISRM International Congress on Rock Meelumics, Aachen, 16-20 September 1991 V1, P793-798. Publ Rotterdam: A A Balkema, 1991 The thrust and bending moment which develop on primary tunnel support during face advance reflect the three dimensional nature of the tunnelling problem. Three dimensional finite element analysis of tunnels in isotropic and transverse isotropic ground is used to examine effects of relative ground and support stiffness, length of excavation round, and support delay on the thrust and bending moment developed. Using
© 1993 Pergamon Press Ltd. Reproduction not permitted
The DEM is used to examine the mechanics of deformation, yield, and load transfer around a borehole in a dense granular medium, simulated by an array of 2D idealised discs. Both hydrostatic and non-hydrostatic stress fields are considered. Annular dilation, nonlinear behaviour, shear zone generation, and the development of borehole breakout can be reasonably simulated. Stress distributions computed using the DEM are compared to those from conventional analytical solutions. 933469 Mechanical effects of pressure and temperature variation on annular cement in oil wells Charara, I; Minh, D N Proc 33rd US Symposium on Rock Mechanics, Santa Fe, 3-5 June 1992 P429-437. Publ Rotterdam: A A Balkema, 1992
The possibility of damage to the cement annulus in a cased oil or gas well as a result of thermal loading due to injection of hot steam or cool mud or mechanical loading as a result of change in internal casing pressure is analysed. The cement is considered linear viscoelastic, the rock elastic or viscoelastic, the steel casing elastic. Parametric study is made to quantify how close the stress state in the cement gets to its failure criterion. Significant extra stresses are found at the cement-casing interface, especially for the case of simultaneous cooling and pressure variation.
Underground excavation failure mechanisms 933470 Failure modes and pillar belmviour in the Zinkgrnvan mine Sjoberg, J Proc 33rd US Symposium on Rock Mechanics, Santa Fe, 3-5 June 1992 P491-500. Publ Rotterdam: A A Balkema, 1992 A tabular, steeply dipping orebody is mined at a distance of 1800m along the strike at the Zinkgruvan mine, Sweden. Mining has now reached the 840m level. Instability problems in stope roofs and sill pillars have been met. Failure modes and local geology have been studied and correlated. Numerical modelling using the UDEC and FLAC codes can reproduce observed modes of failure and MINSIM-D can predict onset of failure. Simple to use stress level criteria for different modes of failure have been developed. The need to identify geological conditions in planning for this mine is emphasised.
Tunnels 933471 Tunnel __detagnand comtrnction Crighton, G S; Biggart, A E; Norie, E H lust Ci~ E q r s Proc Special Issue: The Channel Tunnel P1842, 1992
The design concepts and planning and construction programs for the Channel Tunnel are outlined. The main elements of the scheme are described and development and organisation of the
planning program, site investigation, preconstructional organisation, main features of the NATM tunnels, bored tunnels, and major underground structures, and fitting-out are discussed. 933472 Machine-driven tunnels Chapman, P J; Wrightam, V H; Ince, G; Lewis, R P lust Civ Eugrs Proc Special Issue: The Channel Tunnel P5586, 1992 One major aspect of UK underground work for the Channel Tunnel was 84kin of TBM driven tunnels, which required six machines, each specifically designed and constructed for continuous high-speed working. Factors which were considered in selecting this construction method are outlined. The designs of the TBMs for the pilot tunnel, land running tunnels, and marine running tunnels and their ancillary equipment are illustrated. Tunnelling experiences and the performance achieved are discussed. 933473 Three-dimensional modelllm~ of junctions at the Channel Tunnel Project. Technical note on practical applications Potter, R Int J Num Anal MetA Geomeeli F16, N9, Sept 1992, P683695 The underground marshalling area for the Channel Tunnel project required numerous connections between caverns and tunnels of various sections. Three dimensional finite element analysis of a representative junction was carried out and the impact of the results on engineering practice, in particular design of the final lining, assessed. Construction was according to NATM principles. The importance of combining the FE modelling data with engineering judgement and geological information for design decisions is noted. 933474 Rigorously determined support characteristics and support design method for tunnels subject to squeezing conditions Kirsten, H A D; Bartlett, P J J S Aft lust Min Metall V92, N7, July 1992, P195-214 A rigorous design system for support of tunnels at the Premier Mine in South Africa is required to validate and augment the current empirical NATM-Q system. A 2D numerical simulation based on the finite difference code FLAC is used. Mine layout, mining sequences, and field stresses are outlined. 25 support configurations have been evaluated for a range of tunnel sizes and shapes. Loads on the rock reinforcement around the tunnel have been analysed. It is seen that the empirical design may significantly underestimate support requirements in squeezing ground. 933475 Simulation of rock-liner interaction for tunnels in isotropic and anisotropic rock masses Pelli, F; Kaiser, P; Morgenstern, N R Proc 7th ISRM International Congress on Rock Meelumics, Aachen, 16-20 September 1991 V1, P793-798. Publ Rotterdam: A A Balkema, 1991 The thrust and bending moment which develop on primary tunnel support during face advance reflect the three dimensional nature of the tunnelling problem. Three dimensional finite element analysis of tunnels in isotropic and transverse isotropic ground is used to examine effects of relative ground and support stiffness, length of excavation round, and support delay on the thrust and bending moment developed. Using
© 1993 Pergamon Press Ltd. Reproduction not permitted