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Tunnel boring systems meeting NATM requirements (In German)
217A
Underground excavation failure mechanisms
Tunnels
894384 Geomechanical evaluation of a coal mine arched entry Aggson, J R; Mouyard, D P lnt J Min Geoi Engng V6, N3, Oct 1988, P185-193
See a&o: 894146. 894156, 894238
By constructing an arched opening in the centre entry of a 3 entry system,cutter roof failures in the outside entries were eliminated. In situ strength was determined using borehole deformation gauges and overcoring used to quantify horizontal roof stress in the plane perpendicular to the arch. Measurements showed stress relief from the arch extended over the 2 outside entries, much further than predicted by elastic analysis. Underground observations and boundary element modelling showed the roof rock responded as a system of coupled horizontal members and horizontal discontinuities played a major role in formation of the broad, stress relieved zone. The model could also be used as a calibrated tool to evaluate alternative geometries or other potential methods of dealing with roof control problems.
894385 Analysis of interaction effects on overlying seams by mining an underlying seam Zhou, Y; Haycocks, C; Wu, W Proc 5th Annual Workshop Generic Mineral Technology Center Mine Systems Design and Ground Control, Tusealoosa, 26-27 October 1987 P99-109. Publ Blacksburg: Virginia Polytechnic and State University, 1987 Multiseam extraction is becoming widespread. A program to identify damage types and failure modes, isolate factors affecting overmining interactions, and model possible interactions has been developed. Geological factors, mining variables, and ground control conditions of many case studies have been examined. The failure modes identified were massive shearing, bending of upper seam, local shearing, fracturing, squeezing, and bed separation. Factors influencing failure mode and their effects on the seam were identified. Subsidence effects on the seam are more intense than at the surface.
894386 Prediction of ground movement adjacent to a supported deep foundation EI-Nahhas, F Proc Ninth Regional Conference for Africa on Soil Mechanics and Foundation Engineering, Lagos, September 1987 V1, P285-291. Publ Rotterdam: A A Balkema. 1987 Deep excavations cause a complex deformation field within the surrounding soil mass. To compare methods to predict soil movement, an excavation was constructed on a stiff clay deposit, and settlement and lateral movement of walls monitored. An empirical method and finite element analysis were used to analyse measurements. Results indicate the wide range of settlement values proposed by the empirical method may be reduced when finite element analysis is used.
894387 Tunnel boring systems meeting NATM requirements (In German) Lauffer, H Felsbau V6, N4, Not, 1988. P169-174 TBM applications can be substantially expanded if systems are developed which can cope with large deformations around a tunnel and advance rapidly through fractured or cohesionless ground. Such systems allow support to be adjusted to local conditions on the basis of continuous monitoring and interpretation of ground conditions. Two potential designs are presented, one with support installed immediately behind a small depth cutter head, the other with a variable diameter telescopic shield which may be moved right up to the cutting head.
894388 International developments in drivage technology with particular consideration to full-face cutting technique Boldt, H German Min N2, 1988, P58-64 The bulk of hard headings created today still use drill and blast, although machine drivage is increasing. Improvements in blasthole drilling and blasting, evaluation of drivage through blasted ground, support, and muck removal are considered. The development of the TBM, its applications in coal mining and tunnelling, and areas where its use is advantageous are examined. Some of the more important TBMs are illustrated.
894389 Applicability of the shield method to urban tunnelling Japan Tunnelling Association Tunnlg Underground Space Technol V4. NI, 1989, P53-81 Shield tunnelling is increasingly being used in urban areas as it offers prevention of noise and vibration and reduction of surface disruption. Results of a comprehensive survey of worldwide shield tunnelling operations are presented. Current state includes type of shield, functions of completed tunnels, period of contract, primary lining, outer diameter, advance rate, back fill grouting material, and ground surface settlement. Also discussed are ground water conditions, selection of shield type, shield specifications (thrust mechanism, cutter mechanism, segment handling and machine logistics), stabilisation work, construction costs, problems and future prospects.
894390 Blast monitoring at Penmaenbach Arber, A W; Selley, P Tunn Tunnlg V21, NI, Jan 1989, P49-50 The Penmaenbach road tunnel through hard rhyolite was excavated by drill and blast. Because of an unlined railway tunnel some 60m away, restrictions were placed on permitted vibration levels and times of blasting. 16 geophones were used as vibration sensors, crack monitors were installed in the railway tunnel, and a geological feature (glacial landslip) above the centre section was studied by aerial photography. Results of presplit and bench blast monitoring, support used, and convergence measured are described.
© 1989 Pergamon Press plc. Reproduction not permitted
Underground excavation failure mechanisms
Tunnels
894384 Geomechanical evaluation of a coal mine arched entry Aggson, J R; Mouyard, D P lnt J Min Geoi Engng V6, N3, Oct 1988, P185-193
See a&o: 894146. 894156, 894238
By constructing an arched opening in the centre entry of a 3 entry system,cutter roof failures in the outside entries were eliminated. In situ strength was determined using borehole deformation gauges and overcoring used to quantify horizontal roof stress in the plane perpendicular to the arch. Measurements showed stress relief from the arch extended over the 2 outside entries, much further than predicted by elastic analysis. Underground observations and boundary element modelling showed the roof rock responded as a system of coupled horizontal members and horizontal discontinuities played a major role in formation of the broad, stress relieved zone. The model could also be used as a calibrated tool to evaluate alternative geometries or other potential methods of dealing with roof control problems.
894385 Analysis of interaction effects on overlying seams by mining an underlying seam Zhou, Y; Haycocks, C; Wu, W Proc 5th Annual Workshop Generic Mineral Technology Center Mine Systems Design and Ground Control, Tusealoosa, 26-27 October 1987 P99-109. Publ Blacksburg: Virginia Polytechnic and State University, 1987 Multiseam extraction is becoming widespread. A program to identify damage types and failure modes, isolate factors affecting overmining interactions, and model possible interactions has been developed. Geological factors, mining variables, and ground control conditions of many case studies have been examined. The failure modes identified were massive shearing, bending of upper seam, local shearing, fracturing, squeezing, and bed separation. Factors influencing failure mode and their effects on the seam were identified. Subsidence effects on the seam are more intense than at the surface.
894386 Prediction of ground movement adjacent to a supported deep foundation EI-Nahhas, F Proc Ninth Regional Conference for Africa on Soil Mechanics and Foundation Engineering, Lagos, September 1987 V1, P285-291. Publ Rotterdam: A A Balkema. 1987 Deep excavations cause a complex deformation field within the surrounding soil mass. To compare methods to predict soil movement, an excavation was constructed on a stiff clay deposit, and settlement and lateral movement of walls monitored. An empirical method and finite element analysis were used to analyse measurements. Results indicate the wide range of settlement values proposed by the empirical method may be reduced when finite element analysis is used.
894387 Tunnel boring systems meeting NATM requirements (In German) Lauffer, H Felsbau V6, N4, Not, 1988. P169-174 TBM applications can be substantially expanded if systems are developed which can cope with large deformations around a tunnel and advance rapidly through fractured or cohesionless ground. Such systems allow support to be adjusted to local conditions on the basis of continuous monitoring and interpretation of ground conditions. Two potential designs are presented, one with support installed immediately behind a small depth cutter head, the other with a variable diameter telescopic shield which may be moved right up to the cutting head.
894388 International developments in drivage technology with particular consideration to full-face cutting technique Boldt, H German Min N2, 1988, P58-64 The bulk of hard headings created today still use drill and blast, although machine drivage is increasing. Improvements in blasthole drilling and blasting, evaluation of drivage through blasted ground, support, and muck removal are considered. The development of the TBM, its applications in coal mining and tunnelling, and areas where its use is advantageous are examined. Some of the more important TBMs are illustrated.
894389 Applicability of the shield method to urban tunnelling Japan Tunnelling Association Tunnlg Underground Space Technol V4. NI, 1989, P53-81 Shield tunnelling is increasingly being used in urban areas as it offers prevention of noise and vibration and reduction of surface disruption. Results of a comprehensive survey of worldwide shield tunnelling operations are presented. Current state includes type of shield, functions of completed tunnels, period of contract, primary lining, outer diameter, advance rate, back fill grouting material, and ground surface settlement. Also discussed are ground water conditions, selection of shield type, shield specifications (thrust mechanism, cutter mechanism, segment handling and machine logistics), stabilisation work, construction costs, problems and future prospects.
894390 Blast monitoring at Penmaenbach Arber, A W; Selley, P Tunn Tunnlg V21, NI, Jan 1989, P49-50 The Penmaenbach road tunnel through hard rhyolite was excavated by drill and blast. Because of an unlined railway tunnel some 60m away, restrictions were placed on permitted vibration levels and times of blasting. 16 geophones were used as vibration sensors, crack monitors were installed in the railway tunnel, and a geological feature (glacial landslip) above the centre section was studied by aerial photography. Results of presplit and bench blast monitoring, support used, and convergence measured are described.
© 1989 Pergamon Press plc. Reproduction not permitted