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Development of a mechanistic model for prediction of maximum subsidence and subsidence profile due to longwall mining
128A 902510 Relationship between acoustic emission and permeability of rock under stress Majewska, Z; Marcak. H g i n Sci Tectmol vg, N2, Sept 1989. P169-179
composed of sand and clay layers. Piles were used to support the structure during construction, and dewatering undertaken to lower the groundwater level. Grouting was carried out under the structure prior to excavation. Settlement was monitored during excavation of 2 pilot drifts.
Outburst is generally preceded by high gas pressure, which may be the result of change of permeability. Simultaneous measurements have been made of acoustic emission and permeability of a burst-prone sandstone under triaxial compression. Changes in acoustic emission and permeability occur together at the dilatancy stage. The relation is examined from a theoretical viewpoint. Agreement between experimental and theoretical results suggests that high frequency acoustic emission monitoring is a promising method for predicting gas burst. Field measurements from Poland are presented.
902514 Dams Safety Committee numerical modelling of mining induced surface subsidence - extension of previous study: 'Application of NTJTEP2 to mining under reservoirs' McNabb, K E CSIRO Division of Geomechanics Report N154, June 1988, 30P
902511 Stochastic methods in subsidence problems Litwiniszyn, J Proc International Symposium on Modern Mining Technology, Taian, October 1988 P300-305. Publ Taian: Shandong Institute of Mining and Technology, 1988 Continuum analysis is inadequate to describe the subsidence of a real rock mass over mining workings, which is characterised by random displacements of its elements. Two random walk models are used in a stochastic approach to subsidence prediction. In the first, the walking element does not preserve memory of previous steps, in the second it does. They describe the displacement of the discrete media in the form of parabolic and hyperbolic linear equations, and a nonlinear hyperbolic equation respectively.
Two dimensional finite element analysis of surface subsidence induced by full or partial extraction of a coal seam is presented. Effects of parameters such as linear or nonlinear materials, horizontal and vertical discontinuities, extent and magnitude of roof pulldown, and mining sequence were studied. The 'calibrated' roof pulldown technique did not give valid subsidence profiles for nonlinear materials, due to yield of overburden strata, largely due to tensile fracturing. Horizontal joints or bedding may delaminate, resulting in increased horizontal hydraulic conductivity.
Avail: CSIRO Division of Geomechanics, PO Box 54, Mt Waverley, Vic 3149, Australia
Influence of dynamic loads See also." 902420
902512 Development of a mechanistic model for prediction of maximum subsidence and subsidence profile due to iongwall mining Begley, R D; Khair, A W Rock Mechanics as a Guide for Efficient Utilization of Natural Resources: Proc 30th U.S. Symposium, zWorgantown, 19-22 June 1989 P495-502. Publ Rotterdam." A A Balkema, 1989 A model originally developed for West Virginia has been refined using additional published data. The original predicts maximum subsidence using parameters of mine geometry, angle of draw, and expansion factors of the deformation zones above the excavation. Subsidence profile is predicted using a negative exponential equation. Refinement involves incorporating relations between overburden properties and angle of draw, plus expansion or bulking factors. The final model requires data from mine geometry and site geology. Its application to 10 sites is illustrated. 902513 In-situ measurements and construction control of an underground excavation beneath the subground structure for a subway construction in Nagoya Nakashima, M; Hirata, A; Iwasaki, Y Proc 2nd International Symposium on Field Measurements in Geomechanics, Kobe, 6-9 April 1987 VI, P473-480. Publ Rotterdam: A A Balkema, 1988 Part of the subway system in Nagoya is to pass underneath an underground shopping centre. Studies made to ensure its safety during construction are described. The foundation is
902515 Study on response of buried pipelines subjected to liquefactioninduced permanent ground displacement Miyajima, M; Kitawa, M; Nomura, Y Struct Engng Earthq Engng V6, NI, April 1989, Pl41s-150s Model tests were carried out to investigate the characteristics of permanent ground displacement associated with soil liquefaction. Beam theory is used to understand the fundamental characteristics of pipeline behaviour. Jointed pipes are considered using a modified transfer matrix method. Factors influencing the magnitude of ground movement are examined,and methods to evaluate pipeline response proposed.
902516 Analysis of linings of parallel hydraulic tunnels constructed in seismic regions Fotieva, N N; Bulychev, N S Proc International Symposium Tunnelling for Water Resources and Power Projects, New Dellu', 19-23 January 1988 VI, P327-330. Publ New Delhi: Oxford and IBH Publishing Co, 1988 Stresses on the linings of tunnel complexes differ from those on an isolated tunnel. A procedure for dynamic analysis for linings in a complex of parallel circular tunnels of different radii is presented. The method determines the most adverse stress state in each radial section of each lining for longitudinal and transverse waves in any direction. The method is illustrated for 5 parallel tunnels in a hydraulic project, and for 3 parallel tunnels.
~' 1990 Pergamon Press pie. Reproduction not permitted
composed of sand and clay layers. Piles were used to support the structure during construction, and dewatering undertaken to lower the groundwater level. Grouting was carried out under the structure prior to excavation. Settlement was monitored during excavation of 2 pilot drifts.
Outburst is generally preceded by high gas pressure, which may be the result of change of permeability. Simultaneous measurements have been made of acoustic emission and permeability of a burst-prone sandstone under triaxial compression. Changes in acoustic emission and permeability occur together at the dilatancy stage. The relation is examined from a theoretical viewpoint. Agreement between experimental and theoretical results suggests that high frequency acoustic emission monitoring is a promising method for predicting gas burst. Field measurements from Poland are presented.
902514 Dams Safety Committee numerical modelling of mining induced surface subsidence - extension of previous study: 'Application of NTJTEP2 to mining under reservoirs' McNabb, K E CSIRO Division of Geomechanics Report N154, June 1988, 30P
902511 Stochastic methods in subsidence problems Litwiniszyn, J Proc International Symposium on Modern Mining Technology, Taian, October 1988 P300-305. Publ Taian: Shandong Institute of Mining and Technology, 1988 Continuum analysis is inadequate to describe the subsidence of a real rock mass over mining workings, which is characterised by random displacements of its elements. Two random walk models are used in a stochastic approach to subsidence prediction. In the first, the walking element does not preserve memory of previous steps, in the second it does. They describe the displacement of the discrete media in the form of parabolic and hyperbolic linear equations, and a nonlinear hyperbolic equation respectively.
Two dimensional finite element analysis of surface subsidence induced by full or partial extraction of a coal seam is presented. Effects of parameters such as linear or nonlinear materials, horizontal and vertical discontinuities, extent and magnitude of roof pulldown, and mining sequence were studied. The 'calibrated' roof pulldown technique did not give valid subsidence profiles for nonlinear materials, due to yield of overburden strata, largely due to tensile fracturing. Horizontal joints or bedding may delaminate, resulting in increased horizontal hydraulic conductivity.
Avail: CSIRO Division of Geomechanics, PO Box 54, Mt Waverley, Vic 3149, Australia
Influence of dynamic loads See also." 902420
902512 Development of a mechanistic model for prediction of maximum subsidence and subsidence profile due to iongwall mining Begley, R D; Khair, A W Rock Mechanics as a Guide for Efficient Utilization of Natural Resources: Proc 30th U.S. Symposium, zWorgantown, 19-22 June 1989 P495-502. Publ Rotterdam." A A Balkema, 1989 A model originally developed for West Virginia has been refined using additional published data. The original predicts maximum subsidence using parameters of mine geometry, angle of draw, and expansion factors of the deformation zones above the excavation. Subsidence profile is predicted using a negative exponential equation. Refinement involves incorporating relations between overburden properties and angle of draw, plus expansion or bulking factors. The final model requires data from mine geometry and site geology. Its application to 10 sites is illustrated. 902513 In-situ measurements and construction control of an underground excavation beneath the subground structure for a subway construction in Nagoya Nakashima, M; Hirata, A; Iwasaki, Y Proc 2nd International Symposium on Field Measurements in Geomechanics, Kobe, 6-9 April 1987 VI, P473-480. Publ Rotterdam: A A Balkema, 1988 Part of the subway system in Nagoya is to pass underneath an underground shopping centre. Studies made to ensure its safety during construction are described. The foundation is
902515 Study on response of buried pipelines subjected to liquefactioninduced permanent ground displacement Miyajima, M; Kitawa, M; Nomura, Y Struct Engng Earthq Engng V6, NI, April 1989, Pl41s-150s Model tests were carried out to investigate the characteristics of permanent ground displacement associated with soil liquefaction. Beam theory is used to understand the fundamental characteristics of pipeline behaviour. Jointed pipes are considered using a modified transfer matrix method. Factors influencing the magnitude of ground movement are examined,and methods to evaluate pipeline response proposed.
902516 Analysis of linings of parallel hydraulic tunnels constructed in seismic regions Fotieva, N N; Bulychev, N S Proc International Symposium Tunnelling for Water Resources and Power Projects, New Dellu', 19-23 January 1988 VI, P327-330. Publ New Delhi: Oxford and IBH Publishing Co, 1988 Stresses on the linings of tunnel complexes differ from those on an isolated tunnel. A procedure for dynamic analysis for linings in a complex of parallel circular tunnels of different radii is presented. The method determines the most adverse stress state in each radial section of each lining for longitudinal and transverse waves in any direction. The method is illustrated for 5 parallel tunnels in a hydraulic project, and for 3 parallel tunnels.
~' 1990 Pergamon Press pie. Reproduction not permitted