Numerical modelling of progressive subsidence : Park, D W; Ash, N F Proc 5th annual workshop generic mineral technology center mine systems design and ground control, Tuscaloosa, 26–27 October 1987P111–118. Publ Blacksburg: Virginia Polytechnic and State University, 1987

226A 894457 Crown pillar subsidence prediction from centrifuge models Wizniak, L: Mitchell. R J Proc International Symposium on Prediction and Performance in Geotechnical Engineering, Calgary, 17-19 June 1987 P387- 395. Publ Rotterdam: A A Balkema. 1987 Crown pillar subsidence was modelled using the beam on elas- tic foundation approach of Hetenyi, and a computer analogue written to predict subsidence for the case of nonlinear backfill. Centrifuge simulations were carried out using plain concrete to model crown pillars and conventional cemented tailings backfill. Model tests indicate that tight backfilling can delay beam caving and reduce subsidence. Results of physical and numerical simulations compare favourably. 89446 I Numerical modelling of subsidence induced by underground coal mining Coulthard. M A; Dutton. A J Key Questions in Rock :Wechanics: Proc 29th US Symposium, Minneapolis, 13-15 June 1988 P529-536. Publ Rotterdam. ,4 A Balkema. 1988 Empirical methods of subsidence prediction and previous numerical modelling are briefly outlined. Two dimensional analysis of subsidence due to extraction of a single panel of coal is modelled using nonlinear material models in the pro- grams FLAC (finite element) and UDEC (distinct element). These programs allow realistic modelling of rock strata and can predict the observed qualitative change in subsidence pro- file that occurs in the transition from sub-critical to super- critical panel width. 894458 Prediction of coal outburst Sugawara. K; Kaneko, K; Obara, Y; Aoki, T Proc 6th International Conference on Rock Mechanics, Montreal, 30 ,4ug-lO Sept 1987 V2. PI251-1254. Publ Rotterdam: A ,4 Balkema. 1987 Outburst in the Miike mine, Japan, is described. Failures are associated with large scale shear fractures between sandstone roof and coal seam or between sandstone floor and coal seam. The destressed fractured zone ahead of the face offers some protection from coatburst. Its extent may be determined by in- seam drilling and the rate of destrcssing from acoustic moni- toring. A procedure to calculate advance ratcs with minimum risk of outburst, based on fracture zone data, is presented. 894462 Field geotechnical study of the effects of weak floor strata on underground coal mining in Illinois Chugh, Y P; Chandrashekhar, K; Caudle, R D Key Questions in Rock Mechanics: Proc 29th US Symposium, Minneapolis, 13-15 June 1988 P681-690. Publ Rotterdam: A A Balkema. 1988 The commonly mined seams are generally underlain by weak and thick underclays. Surface subsidence causes problems. Laboratory and field geotechnical studies and analytical stud- ies using the ADINA finite element code were carried out. Instrumentation monitored pillar stress, vertical and horizon- tal movement in individual floor strata, differential roof move- ment, and closure. Surface settlement was primarily due to settlement of pillars into weak floor strata. This may allow a simple subsidence prediction formula to be derived, based on pillar monitoring. 894459 Rockburst research in Canada - 1987 Udd, J E: Hedley. D G F Proc 6th International Conference on Rock Mechanics, Montreal, 30 Aug-lO Sept 1987 V2, P1283-1288. Publ Rotter~hun: A ,4 Balkema. 1987 A brief history of rockburst in Ontario mines, with description of some major e~ents, and a summary of rockburst in Canada is presented. Data acquisition and monitoring systems used are described. Present topics under investigation include enhanced monitoring systems to assess peak particle velocity and energy released, algorithms for prediction of rockburst and preventative measures, and site investigation methods to determine integrity of rock structures. 894463 Ground movements and settlements caused by tunnelling for the Singapore Mass Rapid Transit System Shirlaw, J N; Doran, S Proc Tunnelling '88, London, 18-21 April 1988 P295-314. Publ London: IMM. 1988 Settlements caused by construction of the MRT are analysed. Three topics have been examined: effects of different methods in similar ground; extent and magnitude of consolidation set- tlement; and tunnel/tunnel interaction. In boulder clay, NATM generally produced lower settlements than shield tun- nelling. Compressed air and earth pressure balanced shields gave similar initial settlements in soft clays and sands. The high pore pressures generated above EPB shields lead to con- solidation settlements on dissipation. Tunnel, tunnel interac- tion was small. Effects on adjacent structures are also discussed. 894460 Proposed mechanism of rock failure and rockbursting Zou Daihua; Miller, H D S Proc 6th International Conference on Rock Mechanics, Alontreal, 30 Aug-lO Sept 1987 V2. P1357-1362. Publ Rotterdam: A A Balkema, 1987 Work at the University of British Columbia to identify the mechanism of violent rock failure and precursive behaviour is described. Shear failure is postulated as the basic failure mech- anism. Acoustic emission experiments have been used to sub- stantiate this proposal. A numerical model to simulate the acoustic activity has been developed, which realistically mod- els test results. Numerical results are in good agreement with those from a deep level South African mine. 894464 Numerical modelling of progressive subsidence Park, D W; Ash, N F Proc 5th Annual Workshop Generic Mineral Technology Center Mine Systems Design and Ground Control, Tuscaloosa, 26-27 October 1987 PI I I - I I8. Publ Blacksburg: Virginia Polytechnic and State Unit'ersity, 1987 A new subsidence modelling technique using finite element analysis with the iterative procedure is described. It can simu- late progressive development of subsidence. Failure and stress distribution caused by underground openings can be demon- strated. Realistic material properties can be assigned to differ- ent layers, and geological anomalies and discontinuities can be accommodated. C 1989 Pergamon Press pie. Reproduction not permitted