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Preliminary design of a large cavern for power plant in jointed rock mass
370A
926239 Preliminary design of a large cavern for power plant in jointed rock mass Saini, G S; Prasad, V V R; Swarup, A; Dube, A K Proc International Conference on Mechanics of Jointed and Faulted Rock, Vienna, 18-20 April 1990 P855-858. Publ Rotterdam: A A Balkema, 1990 The development of block theory has allowed joint data to be included in design of underground structures in jointed rock. The case of a powerhouse cavern in jointed basic rock intruded into the country rock is presented. Preliminary design parameters for support specification calculated using block theory are compared to those from Barton's Q system for verification. Satisfactory agreement is seen.
926240 Rockbolt support design using a probabilistic method of key block analysis Tyler, D B; Trueman, R; Pine, R J Rock Mechanics as a Multidisciplinary Science, Proc 32nd US Symposium, Norman, 10-12 July 1991 P1037-1046. Publ Rotterdam. A A Balkema, 1991 A probabilistic keyblock analysis has been developed and is implemented in the computer code B3LHS to examine stability at the South Crofty Mine. Latin hypercube sampling is used to generate random input data. A mechanism of factored risk analysis is used to calculate block apex height for a given level of risk, to allow determination of rock bolt length. Bolt spacing is determined as a function of mean block width. B3HLS and empirical design method support patterns are compared. Once a critical excavation width is reached, the number and size of keyblocks becomes constant, and bolt lengths need not be increased.
Stress analysis See also: 926324
926241 Finite element analysis of three dimensional box-type structures interacting with soil Saetta, A V; Vitaliani, R V Comput Geotech VI2, N3, 1991, P179-208 Soil structure interaction of structures formed by thick plates is studied. It is assumed that the plates rest on a semi-infinite, homogeneous, isotropic elastic half space (Boussinesq hypothesis) or on individual springs (Winkler model) or on a spring layer associated with a stretched membrane (Wieghart hypothesis). Individual horizontal springs are used to take into account soil-structure friction effects. The finite element analysis is obtained by superposition of classical formulations of plane stress and a Mindlin-Reissner bending plate, including shear effects. Numerical results are presented for a box section road tunnel beneath a railway.
926242 Dilatancy hysteresis in rocks: a generalised Ramberg-Osgood approach Hueckel, T Comput Geotech 1/12, N3, 1991, P209-234 A continuum approach to deformational response of rock to cyclic loading is presented. Description of pure damping in a single reload-unload cycle,loop dependence on prior induced damage, effects of previous loading history on the loop, cyclic strain accumulation, and cyclic failure are examined. Assumptions are first stated and principal microstructural damage
mechanisms identified. The model developed is a generalization of the Ramberg-Osgood nonlinear law for hysteresis to a multicomponent stress strain law, including arbitrarily complex and irregular load cycles and taking into account anisotropy induced by previous mechanical damage.
926243 Dampling, cyclic strain buildup and fatigue of rocks: a generalized Ramberg-Osgood approach Hueckel, T Comput Geotech II12, N3, 1991, P235-269 A generalisation of the Ramberg-Osgood model for three dimensional cyclic loading of rocks, formulated using discretised kinematic hardening concepts, was presented in a companion paper. The material functions are interpreted and calibrated. Perfect hysteresis, cyclic accumulation of dilatancy, and fatigue up to failure are simulated for typical loading histories.
926244 Micromechanical features of granular assemblies with planar elliptical particles Rothenburg, L; Bathurst, R J Geotechnique V42, N1, March 1992, P79-95 The constitutive behaviour of planar assemblies of elliptical particles has been examined in numerical simulations using the distinct element method (DEM). Qualitative features of the system similar to sand behaviour are identified. Effects of particle eccentricity on peak friction angle and peak dilatancy are examined in detail. Theoretical developments of previously derived stress-force-fabric relations for circular particles are extended to ellipses. The numerical simulations are used to confirm the proposed relations.
926245 Finite element procedure for calculation of strain from interpolated displacements. Short communication Carr, J R lnt J Num Anal Meth Geomech V16, N3, March 1992, P211225 When a finite element procedure is used to calculate strains based on field measurements of displacement, the displacements at nodal points of a superimposed mesh must first be estimated by interpolation. Two interpolation methods, second-order universal kriging and a local trend model, are compared for this purpose. The interpolation models are tested by randomly sampling displacements obtained in a finite element analysis and attempting to reconstruct the original results by applying interpolation.
926246 Non-linear numerical model for soil mechanics Ng, T T; Dobry, R Int J Num Anal Meth Geomech V16, N4, April 1992, P247263 A new computer program (CONBAL-2) has been developed for 2D numerical simulation of granular soils as random arrays of spheres. It uses the DEM and is based on Cundall's TRUBAL, with implementation of a rigorous solution for the force-displacement relation at the interparticle contacts. This relation has been calibrated to represent sand and CONBAL used to simulate monotonic drained and undrained triaxial tests and cyclic torsion tests for arrays of 531 spheres of two particle sizes. Output agrees qualitatively (and sometimes quantitatively) with laboratory tests on sands, the differences being explainable by simplifications for the model.
© 1992 Pergamon Press Ltd. Reproduction not permitted
926239 Preliminary design of a large cavern for power plant in jointed rock mass Saini, G S; Prasad, V V R; Swarup, A; Dube, A K Proc International Conference on Mechanics of Jointed and Faulted Rock, Vienna, 18-20 April 1990 P855-858. Publ Rotterdam: A A Balkema, 1990 The development of block theory has allowed joint data to be included in design of underground structures in jointed rock. The case of a powerhouse cavern in jointed basic rock intruded into the country rock is presented. Preliminary design parameters for support specification calculated using block theory are compared to those from Barton's Q system for verification. Satisfactory agreement is seen.
926240 Rockbolt support design using a probabilistic method of key block analysis Tyler, D B; Trueman, R; Pine, R J Rock Mechanics as a Multidisciplinary Science, Proc 32nd US Symposium, Norman, 10-12 July 1991 P1037-1046. Publ Rotterdam. A A Balkema, 1991 A probabilistic keyblock analysis has been developed and is implemented in the computer code B3LHS to examine stability at the South Crofty Mine. Latin hypercube sampling is used to generate random input data. A mechanism of factored risk analysis is used to calculate block apex height for a given level of risk, to allow determination of rock bolt length. Bolt spacing is determined as a function of mean block width. B3HLS and empirical design method support patterns are compared. Once a critical excavation width is reached, the number and size of keyblocks becomes constant, and bolt lengths need not be increased.
Stress analysis See also: 926324
926241 Finite element analysis of three dimensional box-type structures interacting with soil Saetta, A V; Vitaliani, R V Comput Geotech VI2, N3, 1991, P179-208 Soil structure interaction of structures formed by thick plates is studied. It is assumed that the plates rest on a semi-infinite, homogeneous, isotropic elastic half space (Boussinesq hypothesis) or on individual springs (Winkler model) or on a spring layer associated with a stretched membrane (Wieghart hypothesis). Individual horizontal springs are used to take into account soil-structure friction effects. The finite element analysis is obtained by superposition of classical formulations of plane stress and a Mindlin-Reissner bending plate, including shear effects. Numerical results are presented for a box section road tunnel beneath a railway.
926242 Dilatancy hysteresis in rocks: a generalised Ramberg-Osgood approach Hueckel, T Comput Geotech 1/12, N3, 1991, P209-234 A continuum approach to deformational response of rock to cyclic loading is presented. Description of pure damping in a single reload-unload cycle,loop dependence on prior induced damage, effects of previous loading history on the loop, cyclic strain accumulation, and cyclic failure are examined. Assumptions are first stated and principal microstructural damage
mechanisms identified. The model developed is a generalization of the Ramberg-Osgood nonlinear law for hysteresis to a multicomponent stress strain law, including arbitrarily complex and irregular load cycles and taking into account anisotropy induced by previous mechanical damage.
926243 Dampling, cyclic strain buildup and fatigue of rocks: a generalized Ramberg-Osgood approach Hueckel, T Comput Geotech II12, N3, 1991, P235-269 A generalisation of the Ramberg-Osgood model for three dimensional cyclic loading of rocks, formulated using discretised kinematic hardening concepts, was presented in a companion paper. The material functions are interpreted and calibrated. Perfect hysteresis, cyclic accumulation of dilatancy, and fatigue up to failure are simulated for typical loading histories.
926244 Micromechanical features of granular assemblies with planar elliptical particles Rothenburg, L; Bathurst, R J Geotechnique V42, N1, March 1992, P79-95 The constitutive behaviour of planar assemblies of elliptical particles has been examined in numerical simulations using the distinct element method (DEM). Qualitative features of the system similar to sand behaviour are identified. Effects of particle eccentricity on peak friction angle and peak dilatancy are examined in detail. Theoretical developments of previously derived stress-force-fabric relations for circular particles are extended to ellipses. The numerical simulations are used to confirm the proposed relations.
926245 Finite element procedure for calculation of strain from interpolated displacements. Short communication Carr, J R lnt J Num Anal Meth Geomech V16, N3, March 1992, P211225 When a finite element procedure is used to calculate strains based on field measurements of displacement, the displacements at nodal points of a superimposed mesh must first be estimated by interpolation. Two interpolation methods, second-order universal kriging and a local trend model, are compared for this purpose. The interpolation models are tested by randomly sampling displacements obtained in a finite element analysis and attempting to reconstruct the original results by applying interpolation.
926246 Non-linear numerical model for soil mechanics Ng, T T; Dobry, R Int J Num Anal Meth Geomech V16, N4, April 1992, P247263 A new computer program (CONBAL-2) has been developed for 2D numerical simulation of granular soils as random arrays of spheres. It uses the DEM and is based on Cundall's TRUBAL, with implementation of a rigorous solution for the force-displacement relation at the interparticle contacts. This relation has been calibrated to represent sand and CONBAL used to simulate monotonic drained and undrained triaxial tests and cyclic torsion tests for arrays of 531 spheres of two particle sizes. Output agrees qualitatively (and sometimes quantitatively) with laboratory tests on sands, the differences being explainable by simplifications for the model.
© 1992 Pergamon Press Ltd. Reproduction not permitted