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Mapping of the excavation damage zone around the circular access shaft at Atomic Energy of Canada Limited's Underground Research Laboratory
185A 9O3435 Geomechanics of underground coal mining under very weak overburden rocks at Huntly East Mine, New Zealand Tan, J K; St George. J D
Min Sci Technoi vg, N3. Not, 1989, P253-265 The elastic-perfectly plastic finite difference code F L A C was used to analyse stress and deformation associated with the Wongawilli method. Results show that with very weak overburden rocks and relatively strong coal strata, traditional design methods cannot ensure safety. Up to 2m of coal must be left bolted to the roadway roof, The barrier pillar must be wide enough to prevent the roadway becoming engulfed by the yield zone associated with the goat', Results were in reasonable agreement with in mine measurements. 903436 Calculation of a nonlinear boundary element method for tunnels supported by anehor-shotcrete Zheng Yingren; Xu Jinyu
Proc International Symposium on Modern Mining Technology, Taian, October 1988 P339-347. Publ Taian: Shandong Institute of Mining and Technology, 1988 The stability of a tunnel in a rock mass containing soft clay strata is analysed using a boundary element approach, with shotcrete support modelled by finite elements, clay strata by fault elements, and anchor forces considered as special body forces. The initial stress method and middle point approximate stiffness method are used in no-tension analysis of the rock mass to determine stresses and displacements. 903437 Back analysis of support loads based on measured displacements: arrangement of measuring locations and determination of measuring tolerance Lu Aizhong
Proc International Symposium on Modern Mining Technology, Taian, October 1988 P362-373. Publ Taian: Shandong Institute of Mining and Technology. 1988 Stability of underground structures may be analysed using results from purpose built monitoring systems or back analysis of loads based on displacements measured at fixed points such as support arches. The latter method is inexpensive but requires complicated calculations and a reliable model of the structure. The selection of reference nodal points on an arch and measurement of absolute displacements are important factors, and their determination using error theory is illustrated. 903438 Influence of soil creep on stress state of the underground structures being built with strengthening of the surrounding massif Fotiyeva, N N; Sammal, A S; Chetyrkin, N S
Proc International Conference on Rheology and Soil Mechanics, Corentry, 12-16 Sept 1988 P248-260. Publ London: Elset'ier. 1988 Where weak and water saturated soils occur, measures are taken to strengthen the massif surrounding underground structures, by grouting the face or lining completely. A method, based on the theory of linear hereditary creep, which considers the rheological properties of soils when determining the stress state of underground structures in a strengthened soil mass is developed. The stress state of the tunnel lining for the case of preconstruction strengthening is shown to differ from that for the case of grouting through the lining. Examples illustrating the development of stresses and displacements in the lining as a function of time and rheological characteristics of the massif are presented.
9O3439 Coal pillar sidewall support at depth Hill, R W
Proc 1st Regional Conference for Africa, Rock Mechanics in Africa, Swaziland, 3-4 November 1988 P255-259. Publ Marshalltown: SANGORM, 1988 At depths greater than 200-300m, stresses in pillar sides in bord and pillar mining exceed coal strength and spalling results. A variety of supports was evaluated in field trials, taking into account economics, availability, and ease of use. Rock bolts, rebar and resin, wooden dowels and resin, split sets and cable trusses were used. The final design adopted wooden dowels in the walls and steel dowels at corners subject to damage by shuttle cars. 903440 Application of the results of excavation response experiments at Climax and the Colorado School of Mines to the development of an experiment for the Underground Research Laboratory Ubbes, W P; Yow, J L; Hustrulid, A
Proc NEA Workshop on Excavation Response in Geological Repositories for Radioactive Waste, Winnipeg, 26-28 April 1988 P245-256. Publ France: OECD, 1989 Excavation response experiments at Climax and the Colorado School of Mines (CSM) have been used to plan such an experiment at the Underground Research Laboratory (URL). At Climax the displacement and stress effects were monitored during excavation and during heater tests, showing the effects of excavation are at least as significant as those from heating. At CSM, excavation response was studied, aiming to minimise blasting damage. Consideration of these results indicates that it is important to measure the fight parameters accurately, to have representative computer models and to understand the existing field situation. Planning at URL includes evaluation and improvement of the ability to predict the mechanical and hydrological response to excavation, determination of geomechanical and hydrological properties of the rock mass, and study of the fundamental mechanisms governing rock mass response. 903441 Mapping of the excavation damage zone around the circular access shaft at Atomic Energy of Canada Limited's Underground Research Laboratory Everitt, R A; Chernis, P; Good, D; Grogan, A
Proc NEA Workshop on Excavation Response in Geological Repositories for Radioactive Waste, Winnipeg, 26-28 April 1988 P271-282. Publ France: OECD. 1989 Excavation damage around a circular shaft extension driven in granite was mapped using stereo photographs as a mapping base. The damage zone is much smaller than that of the original rectangular shaft. Two scales of fracturing are observed. Micro-fractures occur parallel to the direction of maximum principal compressive stress in the horizontal plane, and are thought to be extensional in origin. Mesoscale fractures occur perpendicular to these fractures and their origin is uncertain. 903442 Assessment of excavation disturbance surrounding underground openings in rock Koopmans, R; Hughes, R W
Proc NEA Workshop on Excavation Response in Geological Repositories for Radioactive Waste, Winnipeg, 26-28 April 1988 P283-294. Publ France: OECD, 1989 The borehole dilatometer was used to determine the extent of excavation disturbance around underground openings in crystalline rock and sandstone. The tests were carried out at close
'9 1990 Pergamon Press plc. Reproduction not permitted R M M S 2~ ~ J
Min Sci Technoi vg, N3. Not, 1989, P253-265 The elastic-perfectly plastic finite difference code F L A C was used to analyse stress and deformation associated with the Wongawilli method. Results show that with very weak overburden rocks and relatively strong coal strata, traditional design methods cannot ensure safety. Up to 2m of coal must be left bolted to the roadway roof, The barrier pillar must be wide enough to prevent the roadway becoming engulfed by the yield zone associated with the goat', Results were in reasonable agreement with in mine measurements. 903436 Calculation of a nonlinear boundary element method for tunnels supported by anehor-shotcrete Zheng Yingren; Xu Jinyu
Proc International Symposium on Modern Mining Technology, Taian, October 1988 P339-347. Publ Taian: Shandong Institute of Mining and Technology, 1988 The stability of a tunnel in a rock mass containing soft clay strata is analysed using a boundary element approach, with shotcrete support modelled by finite elements, clay strata by fault elements, and anchor forces considered as special body forces. The initial stress method and middle point approximate stiffness method are used in no-tension analysis of the rock mass to determine stresses and displacements. 903437 Back analysis of support loads based on measured displacements: arrangement of measuring locations and determination of measuring tolerance Lu Aizhong
Proc International Symposium on Modern Mining Technology, Taian, October 1988 P362-373. Publ Taian: Shandong Institute of Mining and Technology. 1988 Stability of underground structures may be analysed using results from purpose built monitoring systems or back analysis of loads based on displacements measured at fixed points such as support arches. The latter method is inexpensive but requires complicated calculations and a reliable model of the structure. The selection of reference nodal points on an arch and measurement of absolute displacements are important factors, and their determination using error theory is illustrated. 903438 Influence of soil creep on stress state of the underground structures being built with strengthening of the surrounding massif Fotiyeva, N N; Sammal, A S; Chetyrkin, N S
Proc International Conference on Rheology and Soil Mechanics, Corentry, 12-16 Sept 1988 P248-260. Publ London: Elset'ier. 1988 Where weak and water saturated soils occur, measures are taken to strengthen the massif surrounding underground structures, by grouting the face or lining completely. A method, based on the theory of linear hereditary creep, which considers the rheological properties of soils when determining the stress state of underground structures in a strengthened soil mass is developed. The stress state of the tunnel lining for the case of preconstruction strengthening is shown to differ from that for the case of grouting through the lining. Examples illustrating the development of stresses and displacements in the lining as a function of time and rheological characteristics of the massif are presented.
9O3439 Coal pillar sidewall support at depth Hill, R W
Proc 1st Regional Conference for Africa, Rock Mechanics in Africa, Swaziland, 3-4 November 1988 P255-259. Publ Marshalltown: SANGORM, 1988 At depths greater than 200-300m, stresses in pillar sides in bord and pillar mining exceed coal strength and spalling results. A variety of supports was evaluated in field trials, taking into account economics, availability, and ease of use. Rock bolts, rebar and resin, wooden dowels and resin, split sets and cable trusses were used. The final design adopted wooden dowels in the walls and steel dowels at corners subject to damage by shuttle cars. 903440 Application of the results of excavation response experiments at Climax and the Colorado School of Mines to the development of an experiment for the Underground Research Laboratory Ubbes, W P; Yow, J L; Hustrulid, A
Proc NEA Workshop on Excavation Response in Geological Repositories for Radioactive Waste, Winnipeg, 26-28 April 1988 P245-256. Publ France: OECD, 1989 Excavation response experiments at Climax and the Colorado School of Mines (CSM) have been used to plan such an experiment at the Underground Research Laboratory (URL). At Climax the displacement and stress effects were monitored during excavation and during heater tests, showing the effects of excavation are at least as significant as those from heating. At CSM, excavation response was studied, aiming to minimise blasting damage. Consideration of these results indicates that it is important to measure the fight parameters accurately, to have representative computer models and to understand the existing field situation. Planning at URL includes evaluation and improvement of the ability to predict the mechanical and hydrological response to excavation, determination of geomechanical and hydrological properties of the rock mass, and study of the fundamental mechanisms governing rock mass response. 903441 Mapping of the excavation damage zone around the circular access shaft at Atomic Energy of Canada Limited's Underground Research Laboratory Everitt, R A; Chernis, P; Good, D; Grogan, A
Proc NEA Workshop on Excavation Response in Geological Repositories for Radioactive Waste, Winnipeg, 26-28 April 1988 P271-282. Publ France: OECD. 1989 Excavation damage around a circular shaft extension driven in granite was mapped using stereo photographs as a mapping base. The damage zone is much smaller than that of the original rectangular shaft. Two scales of fracturing are observed. Micro-fractures occur parallel to the direction of maximum principal compressive stress in the horizontal plane, and are thought to be extensional in origin. Mesoscale fractures occur perpendicular to these fractures and their origin is uncertain. 903442 Assessment of excavation disturbance surrounding underground openings in rock Koopmans, R; Hughes, R W
Proc NEA Workshop on Excavation Response in Geological Repositories for Radioactive Waste, Winnipeg, 26-28 April 1988 P283-294. Publ France: OECD, 1989 The borehole dilatometer was used to determine the extent of excavation disturbance around underground openings in crystalline rock and sandstone. The tests were carried out at close
'9 1990 Pergamon Press plc. Reproduction not permitted R M M S 2~ ~ J