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Rock burst control research by the U.S. Bureau of Mines
49A 891391
Mechanism of seismic events induced by mining: a review Gibowicz. S J
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Miameapofis, 8-10 June 1988, Keynote Presentations P2-121. Publ Minneapolis: University of Minnesota, 1988 Both seismicity directly connected to mining operations and associated with the formation of fractures at the stope face, and that strongly associated with local geology and tectonics on a local and regional scale are included in the review. Double-couple and non-double-couple focal mechanisms, seismic moment tensor, seismic source modelling, seismic spectra and source parameters, scaling relations, attenuation and scattering effects are examined. Attention is paid to practical aspects of waveform data analysis adopted from relevant natural seismicity studies, illustrated using in-mine data. 168 refs. 891392 Mechanics of 'bumps' in coal mines: a discussion of violent deformations in the sides of roadways in coal seams
Lippmann, H
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Minneapolis, 8-10 June 1988, Keynote Presentations P160-171. Publ Minneapolis: University of Minnesota, 1988 The general stress state around underground openings is first considered. The behaviour of materials which fail gradually or which show strong dynamic effects are examined, with attention being paid to uniaxial compression, to find specific properties related to 'proneness to bursting'. Structural approaches to the project are also surveyed. An elementary structural model is developed which can be used to examine risk of rockburst. A rheologic model with anomalous elasticplastic coupling is proposed to describe burst prone materials. 73 refs. 891393 Rock stress, structure and mine design Brady, B H G
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Minneapolis, 8-10 June 1988, Keynote Presentations P175-212. Publ Minneapolis: University of Minnesota, 1988 Outbursts continue to occur in hard rock and coal mines. Conditions where rockburst is likely, models of instability, and seismic event parameters are examined. Three computational techniques to analyse instability are discussed: boundary elements; large scale finite difference methods for elastoplastic analysis; and distinct elements for analysis of true discontinuum behaviour. Applications of these techniques to mine planning,designed to identify burst prone conditions and plan layouts to minimise outburst, are considered. Finally, hydraulic injection of slip prone features as a destressing technique is analysed. 46 refs. 891394 Rock burst control research by the U.S. Bureau of Mines
Bolstad, D D
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Minneapolis, 8-10 June 1988, Keynote Presentations P215-225. Publ Minneapolis: University of Minnesota. 1988 Work at the USBM, often in cooperation with bodies from other countries, is described. The main aims are to determine source and trigger mechanisms and to forecast and control rockburst. Solutions include rock mass modification and the adoption of mining practices to minimise high stress buildup.
The underhand Iongwall method has been developed and its use and its modelling are described. The relation between geology and rockburst is also under investigation. The effect of rockburst on support and its mitigation are studied using large scale laboratory and field testing. 891395
Effect of surcharge loading on ground surface ¢raeklng Habibian, A
Proe Eigkth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Kyoto, 20-24 July 1987 VI, P3740. Publ Japan: Japanese Society for Soil Mechanics and Foundation Engineering, 1987 Centrifuge model tests were carried out to investigate the effect of surcharge loading on the development of tension cracks due, for instance, to depletion of a reservoir, or mining beneath a structure or surface heave. A perimeter crack is seen around the loaded area, which prevents cracking of the ground under the surcharge. Elastic analysis was used to analyse the cracking. The pattern of surface cracks can be reasonably simulated, but ground movements, especially after significant surface cracking, cannot be accurately modelled.
Influence of dynamic loads 891396 Analysis of continuous buried pipelines for seismic wave effects
O'Rourke, M J; El Hmadi, K
Earthq Engng Struct Dynam VI6. N6, Aug 1988. P917-929 Effects of seismic wave propagation on straight continuous buried pipelines are studied. Results indicate that surface waves can cause substantially larger ground strains than body waves, and it is suggested that surface wave propagation be assumed for design purposes. An elastic model of a pipe surrounded by equivalent soil springs indicates frictional slip between soil and pipeline is likely at large ground strains. A method for estimation of ground strains is reviewed, and an analysis procedure for surface wave effects on buried pipes presented and illustrated. 891397 Hangingwall behaviour in tabular stopes subject to seismic events
Kirsten, H A D; Stacey, T R
J S Afr Min Metall V88, NS, May 1988, P163-172 Potential failure mechanisms of underground stopes during seismic events are identified, and simple calculations to evaluate stability of hangingwaU and footwall strata at the working face and in backfilled areas are presented. Backfill reduces the stope span, damps vibration, and prevents fallout of separated blocks in filled areas. Maximum benefit is found if fill is placed as close to the face as possible. 891398 Transient analysis in rock dynamics - some problems and solution strategies
Alheid, H J; Hinzen, K G; Honecker, A; Sarfeld, W
Proc ECONMIG 86, Stuttgart, 16-18 September 1986 I/2, 12P. Publ Stuttgart: University of Stuttgart, 1986 Spatial discretization requirements for dynamic finite element analysis of underground structures necessitate a very large number of nodes, especially in complex geology. Due to computer storage and time limitations, it is often impossible to include source, travel path, and structure in a single discretization. To overcome this problem, a procedure to separate signal flow from the source to the structure into steps and to combine the solutions to get the dynamic response is presented.
© 1989 Pergamon Press pie. Reproduction not permitted
Mechanism of seismic events induced by mining: a review Gibowicz. S J
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Miameapofis, 8-10 June 1988, Keynote Presentations P2-121. Publ Minneapolis: University of Minnesota, 1988 Both seismicity directly connected to mining operations and associated with the formation of fractures at the stope face, and that strongly associated with local geology and tectonics on a local and regional scale are included in the review. Double-couple and non-double-couple focal mechanisms, seismic moment tensor, seismic source modelling, seismic spectra and source parameters, scaling relations, attenuation and scattering effects are examined. Attention is paid to practical aspects of waveform data analysis adopted from relevant natural seismicity studies, illustrated using in-mine data. 168 refs. 891392 Mechanics of 'bumps' in coal mines: a discussion of violent deformations in the sides of roadways in coal seams
Lippmann, H
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Minneapolis, 8-10 June 1988, Keynote Presentations P160-171. Publ Minneapolis: University of Minnesota, 1988 The general stress state around underground openings is first considered. The behaviour of materials which fail gradually or which show strong dynamic effects are examined, with attention being paid to uniaxial compression, to find specific properties related to 'proneness to bursting'. Structural approaches to the project are also surveyed. An elementary structural model is developed which can be used to examine risk of rockburst. A rheologic model with anomalous elasticplastic coupling is proposed to describe burst prone materials. 73 refs. 891393 Rock stress, structure and mine design Brady, B H G
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Minneapolis, 8-10 June 1988, Keynote Presentations P175-212. Publ Minneapolis: University of Minnesota, 1988 Outbursts continue to occur in hard rock and coal mines. Conditions where rockburst is likely, models of instability, and seismic event parameters are examined. Three computational techniques to analyse instability are discussed: boundary elements; large scale finite difference methods for elastoplastic analysis; and distinct elements for analysis of true discontinuum behaviour. Applications of these techniques to mine planning,designed to identify burst prone conditions and plan layouts to minimise outburst, are considered. Finally, hydraulic injection of slip prone features as a destressing technique is analysed. 46 refs. 891394 Rock burst control research by the U.S. Bureau of Mines
Bolstad, D D
Proc 2nd International Symposium of Rockbarsts and Seismicity in Mines, Minneapolis, 8-10 June 1988, Keynote Presentations P215-225. Publ Minneapolis: University of Minnesota. 1988 Work at the USBM, often in cooperation with bodies from other countries, is described. The main aims are to determine source and trigger mechanisms and to forecast and control rockburst. Solutions include rock mass modification and the adoption of mining practices to minimise high stress buildup.
The underhand Iongwall method has been developed and its use and its modelling are described. The relation between geology and rockburst is also under investigation. The effect of rockburst on support and its mitigation are studied using large scale laboratory and field testing. 891395
Effect of surcharge loading on ground surface ¢raeklng Habibian, A
Proe Eigkth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Kyoto, 20-24 July 1987 VI, P3740. Publ Japan: Japanese Society for Soil Mechanics and Foundation Engineering, 1987 Centrifuge model tests were carried out to investigate the effect of surcharge loading on the development of tension cracks due, for instance, to depletion of a reservoir, or mining beneath a structure or surface heave. A perimeter crack is seen around the loaded area, which prevents cracking of the ground under the surcharge. Elastic analysis was used to analyse the cracking. The pattern of surface cracks can be reasonably simulated, but ground movements, especially after significant surface cracking, cannot be accurately modelled.
Influence of dynamic loads 891396 Analysis of continuous buried pipelines for seismic wave effects
O'Rourke, M J; El Hmadi, K
Earthq Engng Struct Dynam VI6. N6, Aug 1988. P917-929 Effects of seismic wave propagation on straight continuous buried pipelines are studied. Results indicate that surface waves can cause substantially larger ground strains than body waves, and it is suggested that surface wave propagation be assumed for design purposes. An elastic model of a pipe surrounded by equivalent soil springs indicates frictional slip between soil and pipeline is likely at large ground strains. A method for estimation of ground strains is reviewed, and an analysis procedure for surface wave effects on buried pipes presented and illustrated. 891397 Hangingwall behaviour in tabular stopes subject to seismic events
Kirsten, H A D; Stacey, T R
J S Afr Min Metall V88, NS, May 1988, P163-172 Potential failure mechanisms of underground stopes during seismic events are identified, and simple calculations to evaluate stability of hangingwaU and footwall strata at the working face and in backfilled areas are presented. Backfill reduces the stope span, damps vibration, and prevents fallout of separated blocks in filled areas. Maximum benefit is found if fill is placed as close to the face as possible. 891398 Transient analysis in rock dynamics - some problems and solution strategies
Alheid, H J; Hinzen, K G; Honecker, A; Sarfeld, W
Proc ECONMIG 86, Stuttgart, 16-18 September 1986 I/2, 12P. Publ Stuttgart: University of Stuttgart, 1986 Spatial discretization requirements for dynamic finite element analysis of underground structures necessitate a very large number of nodes, especially in complex geology. Due to computer storage and time limitations, it is often impossible to include source, travel path, and structure in a single discretization. To overcome this problem, a procedure to separate signal flow from the source to the structure into steps and to combine the solutions to get the dynamic response is presented.
© 1989 Pergamon Press pie. Reproduction not permitted