- Email: [email protected]
Application of block theory in weathered rock
31A 941240 Field measurements applied to the construction of an underground railway station in Milan Stella, C; Castelloti, U Proc 3rd International Symposium on Field Measurements in Geomechanics, Oslo , 9-11 September 1991 V2 , P717-728. Publ Rotterdam: A A Balkema, 1991 Construction of the Repubblica station required excavation of a large, shallow underground opening in sandy-gravelly alluvium, close to a 29 storey building. M W D energy logs were used to resolve the soil profile, and consolidation by cement and chemical grouting carried out. A comprehensive monitoring system was installed to ensure ground movements were within limits. Finite element back analysis of instrumental data allowed modifications and optimization of the grouting and excavation procedures as the project continued.
Analysis Techniques and Design Methods
and two faults identified. The slide mechanism and block stability of the slope have been evaluated using block theory and discontinuous deformation analysis. 941244 Physical and discrete element models of excavation and failure in jointed rock Barton, N Proc International Symposium on Assessment and Prevention o f Failure Phenomena in Rock Engineering, lstanbul, 5-7 April 1993 P35-46. Publ Rotterdam: A A Balkema, 1993 Physical modelling can assist in study of behaviour and failure of rock masses and validation of numerical models. Where large strains occur and continuum assumptions break down, discrete element numerical models are widely used. Examples are given of physical and UDEC-BB modelling of an overstressed borehole and large caverns. In the latter case, numerical results are validated against data from a well-instrumented excavation. The importance of including shear-induced dilatancy and associated joint roughness effects in these models is emphasised.
Stress analysis Rock block analysis 941241 Rock block analysis at Mount Rushmore National Memorial Boyle, W J; Vogt, T J Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3-5 June 1992 P743-750. Publ California: Lawrence Berkeley Laboratory, 1992 Concern has been raised about long term stability of the Mount Rushmore National Memorial, excavated in jointed pegmatitic granite. Extensive mapping of the discontinuities in the sculpture and the unfinished hall has been carried out. The most likely cause of instability is movement of rock blocks bounded by discontinuities. Active sealing prevents creation of new blocks by environmental forces. Structural stability of the blocks identified and possible need for support are being analysed using Goodman and Shi block theory. 941242 Application of block theory in weathered rock Nishigaki, Y; Miki, S Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3-5 June 1992 P779-784. Publ California: Lawrence Berkeley Laboratory, 1992 Block theory is rarely applied in weathered rock as discontinuities are not clearly defined. A method to delineate such discontinuities using statistical analysis of video images of borehole walls is presented. Equipment used is illustrated. The three dimensional configuration so obtained was successfully applied in design of a cut slope in weathered rock using Goodman and Shi maximum key block theory. 941243 Analysis of block stability and discontinuous deformation for a rock slope of dam abutment Pei, J M; Shi, G H Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3-5 June 1992 P785-789. Publ California: Lawrence Berkeley Laboratory, 1992 A large rockslide occurred during excavation of the left abutment slope of the Main-wan dam in China. The rhyolite and pyroclastic rock mass has been mapped and four sets of joints RMMS 3 H - - I
See also: 941072, 941100, 941185 941245 Finite element study of the pressuremeter test in sand using a nonlinear elastic model Fahey, M; Carter, J P Can Geotech J V30, N2, April 1993, P348-362 The hyperbolic model, adjusted by empirical curve fitting, is a useful basis for description of the nonlinear behaviour of sand. To obtain realistic in situ stiffness values it is necessary to use field data as laboratory reconstituted sands cannot reproduce stress history and ageing effects. Finite element analysis of a pressuremeter test is presented, with sand represented by a hyperbolic model. Effects of varying some model parameters on behaviour in load-unload loops are examined and simulations compared to high quality field data. Further work is required to verify some features of the model. 941246 Cone models for a nearly incompressible soil Meek, J W; Wolf, J P Earthq Engng Struct Dynam 1122, N8, Aug /993, P649-663 The cone model can be used for soils in a unified strength of materials approach. For nearly incompressible soils (Poisson's ratio between 1/3 and 1/2) special considerations are required to properly represent vertical and rocking motions. The appropriate wave velocity is taken as twice the S wave velocity, not the P wave velocity, and a trapped mass which increases linearly with Poisson's ratio is included. This mass can be assigned to the base mat, allowing the cone model to be constructed in the same way for all Poisson's ratios. Applications for surface and embedded foundations are shown. 941247 Modeling stress-strain and dilatant behaviour of cohesionless soil Faruque, O; Zaman, M M; Abdumrahee, A indian Geotech J V22, N3, July 1992, PI75-195 A new model for the deformation of cohesionless soils is presented, based on the concept of two characteristic states and their representation as characteristic state lines. The first represents the state of the soil at failure, the second the state at which the mode of deformation switches from compressive to
Analysis Techniques and Design Methods
and two faults identified. The slide mechanism and block stability of the slope have been evaluated using block theory and discontinuous deformation analysis. 941244 Physical and discrete element models of excavation and failure in jointed rock Barton, N Proc International Symposium on Assessment and Prevention o f Failure Phenomena in Rock Engineering, lstanbul, 5-7 April 1993 P35-46. Publ Rotterdam: A A Balkema, 1993 Physical modelling can assist in study of behaviour and failure of rock masses and validation of numerical models. Where large strains occur and continuum assumptions break down, discrete element numerical models are widely used. Examples are given of physical and UDEC-BB modelling of an overstressed borehole and large caverns. In the latter case, numerical results are validated against data from a well-instrumented excavation. The importance of including shear-induced dilatancy and associated joint roughness effects in these models is emphasised.
Stress analysis Rock block analysis 941241 Rock block analysis at Mount Rushmore National Memorial Boyle, W J; Vogt, T J Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3-5 June 1992 P743-750. Publ California: Lawrence Berkeley Laboratory, 1992 Concern has been raised about long term stability of the Mount Rushmore National Memorial, excavated in jointed pegmatitic granite. Extensive mapping of the discontinuities in the sculpture and the unfinished hall has been carried out. The most likely cause of instability is movement of rock blocks bounded by discontinuities. Active sealing prevents creation of new blocks by environmental forces. Structural stability of the blocks identified and possible need for support are being analysed using Goodman and Shi block theory. 941242 Application of block theory in weathered rock Nishigaki, Y; Miki, S Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3-5 June 1992 P779-784. Publ California: Lawrence Berkeley Laboratory, 1992 Block theory is rarely applied in weathered rock as discontinuities are not clearly defined. A method to delineate such discontinuities using statistical analysis of video images of borehole walls is presented. Equipment used is illustrated. The three dimensional configuration so obtained was successfully applied in design of a cut slope in weathered rock using Goodman and Shi maximum key block theory. 941243 Analysis of block stability and discontinuous deformation for a rock slope of dam abutment Pei, J M; Shi, G H Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3-5 June 1992 P785-789. Publ California: Lawrence Berkeley Laboratory, 1992 A large rockslide occurred during excavation of the left abutment slope of the Main-wan dam in China. The rhyolite and pyroclastic rock mass has been mapped and four sets of joints RMMS 3 H - - I
See also: 941072, 941100, 941185 941245 Finite element study of the pressuremeter test in sand using a nonlinear elastic model Fahey, M; Carter, J P Can Geotech J V30, N2, April 1993, P348-362 The hyperbolic model, adjusted by empirical curve fitting, is a useful basis for description of the nonlinear behaviour of sand. To obtain realistic in situ stiffness values it is necessary to use field data as laboratory reconstituted sands cannot reproduce stress history and ageing effects. Finite element analysis of a pressuremeter test is presented, with sand represented by a hyperbolic model. Effects of varying some model parameters on behaviour in load-unload loops are examined and simulations compared to high quality field data. Further work is required to verify some features of the model. 941246 Cone models for a nearly incompressible soil Meek, J W; Wolf, J P Earthq Engng Struct Dynam 1122, N8, Aug /993, P649-663 The cone model can be used for soils in a unified strength of materials approach. For nearly incompressible soils (Poisson's ratio between 1/3 and 1/2) special considerations are required to properly represent vertical and rocking motions. The appropriate wave velocity is taken as twice the S wave velocity, not the P wave velocity, and a trapped mass which increases linearly with Poisson's ratio is included. This mass can be assigned to the base mat, allowing the cone model to be constructed in the same way for all Poisson's ratios. Applications for surface and embedded foundations are shown. 941247 Modeling stress-strain and dilatant behaviour of cohesionless soil Faruque, O; Zaman, M M; Abdumrahee, A indian Geotech J V22, N3, July 1992, PI75-195 A new model for the deformation of cohesionless soils is presented, based on the concept of two characteristic states and their representation as characteristic state lines. The first represents the state of the soil at failure, the second the state at which the mode of deformation switches from compressive to