Tunnel rock displacements and support loads in sheared shale masses

243A of swelling clay zones, and tunnel linings are described. Collapse, and its prediction, prevention and remedial measures are discussed. 904370 Transvaal tribulations Bullent, S Worm Tunnlg V2. N6, Dec 1989, P423-426 The Princeton section of the Agnes gold mine was abandoned in 1943 at depth 60m, due to presence of sulphides and water ingress. To enable its opening at greater depth, a 4kin long tunnel through weathered, vertically dipping, blocky laminated shales and quartzite was planned. Excavation by drill and blast progressed with only moderate support until a talc phyllite zone was encountered. Although alternative solutions were examined, pre-coilapse and reconsolidation, despite its slowness, was the preferred method to traverse this zone. 904371 Environmental aspects of underground space development in Kansas City, USA Hasan, S E Proc Symposium on Environmental Geotechnics and Problematic Soils and Rocks, Bangkok, December 1985 P247253. Publ Rotterdam: A A Balkema. 1988 The conversion of abandoned limestone mines to useable space began in the 1950s. Mining still continues and more space becomes available each year. Geology of the area is described. Past uncontrolled mining and weathering and erosion problems have led to surface collapse, and mine floor heave and groundwater pollution problems have been encountered. These problems should be addressed by optimising mine design and support, identification of potentially unstable areas associated with historic, present, or projected mining, and careful monitoring. 904372 Tunnel rock displacements and support loads in sheared shale mass4~

Cording, E J; Phienweja, N Proc International Symposium on Underground Engineering, New Delhi, 14-17 April 1988 VI, P113-120. Publ Rotterdam: A A Balkema, 1988 The 13kin long Stillwater Tunnel in Utah, USA, passes through Precambrian shales containing an anticlinal fold that has been subject to major faulting. The initially used TBM was unable to advance in the faulted region and was replaced by TBMs with yieldable shields, which could adapt to the squeezing ground. Support loads and closure continued to increase with time at decreasing rate. Deformation was related to both face advance and time dependent effects, the former component being less than if drill and blast were used. Lightweight annular steel ribs, then backfilled concrete segmental lining were used as support.

Stresses around undergroundopenings See also: 904098, 904153, 904274, 904287 904373 Generalization of Galin's problem to frictional materials and discontinuous stress fields Tokar, G lnt J Solids Struct V26, N2, 1990, P129-147 The form of the plastic zone around a circular hole in an inhomogeneous stress field is discussed. Plane strain conditions and a plastic zone enclosing the hole are assumed. The

stress field represents biaxial loading and an overlayed bending. Continuity and discontinuity of circumferential stresses at the elastoplastic boundary are considered. A corrected analytical solution, based on that of Galin (1946), is presented for material obeying Tresca's yield criterion, and a quasi-analytical one of Mohr-Coulomb material. 904374 Subsurface ground strain and fracture development associated with Iongwall mining Whittaker, B N; Gaskell, P; Reddish, D J Min Sci Teehnol VIO, NI, Jan 1990, P71-80 Physical modelling using self-body loading models made from low strength sand and plaster mixes was used to examine ground behaviour above longwali faces under different geological conditions. Planes of weakness were simulated by sawdust spread between layers of the model material. Development of subsurface fractures and resulting principal strain profiles are described and their relations to width and height of the extraction, geological conditions, faulting and water hazards discussed. 904375 Method of determining mechanical parameters of rock Wu Kaihua Proc International Symposium on Modern Mining Technology, Taian, October 1988 P403-409. Publ Taian: Shandong Institute of Mining and Technology, 1988 A method to determine absolute values of initial stress components and equivalent material elastic constants of a jointed rock mass based on in situ measurement of displacements in tunnels is presented. Displacements before measurements commenced are predicted using Grey System Theory, and the mixed method of penalty functions and boundary element analysis. An example is presented and accuracy of results discussed. 904376 Crush pillar design at New Denmark Colliery Wiggett, C H; Claeys, W D Proc 1st Regional Conference for Africa, Rock Mechanics in Africa, Swaziland, 3-4 November 1988 t)327-332. Publ Marshal[town: SANGO RM, 1988 At New Denmark, design studies were carried out to assess pillar systems capable of adequately protecting the tailgate end of Iongwall panels but which crush in the goat', minimising surface subsidence effects and preventing build up of excessive abutment stress caused by an unfailed dolerite sill. Two boundary element programs were used to model stress distribution, with input parameters determined from monitoring the first longwall panel. Computations and field performances are discussed. 904377 Computer simulation of a shaft pillar extraction at Durban Roodepoort Deep, Ltd. James, J V; de Souza, J B Proc Ist Regional Conferencefor Africa,Rock Mechanics in Africa, Swaziland, 3-4 November 1988 P339-354. Publ Marshalltown: SANGORM. 1988 Two steeply dipping seams are mined in the 5 shaft area. In situ stress measurements show maximum principal stress dipping perpendicular to the bedding. Various mining configurations were considered for extraction of the shaft pillar, with limitation of stress and displacement levels whilst maintaining production requirements. Effects of extraction were modelled using the stress analysis program MS 221 and by MINSIM D.

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