Tunnelling developments in Sweden's arctic wastes

Tunnelling developments in Sweden's arctic wastes

262A 934434 Large borehole breakout? Stacey, T R; Thompson, P W Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16-20 September 1991 1...

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262A 934434 Large borehole breakout? Stacey, T R; Thompson, P W Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16-20 September 1991 1/2, P1019-1021. Publ Rotterdam. A A Balkema, 1991 The term borehole breakout is generally associated with wellbores, but there is no reason in principle why it should not be applied to failures in large openings such as shafts or tunnels. Cases of such phenomena have been reported in deep tunnels in kimberlite at the Finsch Mine, South Africa. The machine driven tunnels, with less disturbed rock than blasted tunnels, are more prone to breakout behaviour. Analysis of one case using buckling theory indicates spall dimensions in good agreement with those observed. 934435 Ultra-close seam failure mechanisms Akram, M; Haycocks, C; Haycocks, S G; Karmis, M

Proc 9th Annual Workshop Generic Mineral Technology Center Mine Systems Design and Ground Control, Lexington, 10-12 November 1991 P73-79. Publ Blacksburg: Virginia Polytechnic Institute and State University, 1991 The innerburden is a major structural feature in ultra-close seam mining. Lithology, thickness, pillar size, and mine layout all play a part in controlling innerburden failure mechanisms. Innerburden characterisation is described. Loading conditions of the innerburden are examined, considering cases of self loading and partially and fully offset pillars. Finite element stress analysis with a Mohr Coulomb failure criterion has been used to study methods for improving stability. Effects of localised loading of the upper seam, high horizontal stress fields, and mine layout are discussed. 934436 Hazard approach to multi-seam reserve determination Fraher, R; Sellami, M; Haycocks, C; Karmis, M Proc 9th Annual Workshop Generic Mineral Technology

Center Mine Systems Design and Ground Control, Lexington, 10-12 November 1991 P81-89. Publ Blacksburg: Virginia Polytechnic Institute and State University, 1991 Interactions between seams in multiseam mining can significantly affect the amount of coal that can be recovered. A hazard map approach has been adopted to quantify the degree of interaction across a seam. The initial product was the program U-SEAM, which calculates safety factors against shear failure in the lower seam roof. These safety factors are contoured to produce a hazard map. Mine development can be superimposed on this map to enable unsuitable areas to be avoided.

Tunnels See also." 934159, 934164, 934284 934437 Storehaelt Eastern Railway Tunnel - review of construction works Praesius, P; Townsend, J W Felsbau VIO, N4, Nov 1992, P172-178 The East Tunnel of the Great Belt Project consists of twin tubes of 7.9km length, inner diameter 7.7m. The tunnel is located in tills and fissured marls. In mid-channel the marls are exposed to the sea bed and the groundwater is highly saline. The TBMs used are designed to operate in the open or earth pressure balanced mode with pressure up to 8bar. Lining is

400mm thick precast segments of low permeabdity chlorideresistant concrete, with fusion bonded coated epoxy reinforcement. Construction commenced in 1988 and is expected to bc complete in 1994. 934438 Developments in geotechnical engineering research: applications to tunnels and deep excavations Mair, R J inst Civ Engrs Proc Civ Engng V97, NI, Feb 1993, P27-41 The 1992 Unwin Memorial Lecture. A number of recent advances in geotechnical engineering and their practical applications are described, including methods for soil sampling in difficult strata, improved strain and pore pressure measurement in triaxial tests, and use of pressuremeters to allow better understanding of soil behaviour. Variation of soil stiffness with strain has been studied and used in prediction of ground behaviour. Electrolevels are now used in monitoring ground movement. Bored tunnel construction in hard clay is described, where ground movements were significantly reduced by use of a pilot tunnel. Ground movements due to deep excavations in fill over London Clay are also described. 934439 Tunnelling developments in Sweden's arctic wastes Darling, P Tann Tnnnlg V24, N12, Dec 1992, P31-35 The Klippen hydroelectric project on the Umea river required an 1lkm long,6.5m diameter tunnel, through both crystalline and sedimentary rocks, with some blocky and fragmented zones. A single TBM drive was chosen ahead of drill and blast on the grounds of construction time and hydrodynamic efficiency of the tunnel. The machine developed required large disc cutters to apply the high loads and this necessitated water cooled bearings. Automatic thrust constant (ATC) and variable speed drive (VSD) proved invaluable in coping with the mixed face conditions. The tunnel was largely self-supporting. 92A.A.A.9 Slurry shield tunnelling for Mexico City drainage Schmitter, J M; Lopez, R R Tunn Tunalg V25, NI, Jan 1993, P41-44 Over the past 9 years, more than 30kin of drainage tunnels have been driven in the very soft lacustrine clays of Mexico City. A typical soil profile is shown. Two 6.24m diameter and one 4m diameter slurry shield TBMs have been used. The design of one machine is illustrated, including the triple seal system for primary lining installation. Advance rates achieved on several projects are given. Settlements are considerably less than those found previously, when compressed air tunnelling was used. 934441 Mechanized excavation of the Rovereto hydraulic tunnel Grandori, R; Lembo-Fazio, A; Ribacchi, R Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16-20 September 1991 II2, P995-1000. Publ Rotterdam." A A Balkema, 1991 The Rovereto tunnel is 3km long, 3.5m diameter, and was driven through bedded Jurassic-Triassic limestone and dolomite characterised by high strength and generally widely spaced joints. A full face shield TBM was used. The geological setting and geotechnical characteristics of the rocks are outlined. Machine performance in the various geotechnical zones and associated support, cutter performance, and causes of cutter replacement are discussed.

© 1993 Pergamon Press Ltd. Reproduction not permitted