Opencast extraction of protection pillars in the Carmaux coalfield

250A 885389 Free field earthquake ground motions: effects of various numerical simulation approaches on soil-structure interaction results Krauthammer, T; Chen, Y Engng Struct VIO, N2, April 1988, P85-94 Several approaches for free field motion simulation have been proposed. Relations between type and accuracy of free field input motion generation and resulting effects on surface, partially buried, and embedded structures are examined for three finite element based simulation models. Results indicate that simulation accuracy is a critical factor in determining response, and suggest that some traditional simulation methods may significantly underestimate structural response. 885390 Prediction of lateral displacement of anchored bulkheads induced by seismic liquefaction Towhata, I; Islam, M S Soils Found V27, N4, Dec 1987, Pl37-147 A numerical method to predict lateral displacement of sheetpile anchored bulkheads subject to backfill liquefaction during earthquakes is presented. The method analyses the limit equilibrium of a backfill soil wedge under the action of pseudostatic seismic force, and calculates the critical acceleration of an earthquake necessary to activate the sliding mechanism. Using Newmark's sliding block theory, seismic acceleration in~xcess of the critical value is integrated twice with time so that permanent displacement may be obtained. Parametric studies illustrate use of the method. 88539 I Displacements from loads over rectangular areas: technical note Vitone, D M A; Valsangkar, A J Soils Found V27, 3/4. Dec 1987, P153-156 Solutions are presented for the determination of displacement beneath loaded and unloaded corners of an optimally designed rectangular footing. The method is illustrated using a design example.

Underground Excavations See also: 885180 885392 Advances in technology for the construction of deepunderground facilities U.S. National Committee on Tunneling Technology and U.S. National Committee for Rock Mechanics Tunnlg Underground Space Tecimol V3, NI. 1988, P25-44 Current technological capabilities for deep underground excavation are considered in 4 categories: (I) geotechnical characterisation, including testing and monitoring techniques; (2) design considerations, such as effects of depth and monitoring; (3) construction issues, including geotechnical exploration, effects of depth, excavation and support; and (4) excavation equipment and systems, such as machinery for tunnelling, intersections and cross cuts, and access shaft excavation, and excavation methods. Technology for deep construction is available.

Geological factors of importance in underground excavations 885393 Opencast extraction of protection pillars in the Carmaux coalfield Grandjean, A; Henrich, J F; Hantz, D; Vuillaume, P Proc 13th World Mining Congress, Improvement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 VI, P347-355. Publ Rotterdam: A A Balkema, 1987 Underground operations are complete in the Carmaux coalfield. Remaining protection pillars will be extracted by opencast methods. This is a technically and economically delicate operation due to the size of the pit to be excavated, the geological conditions and the high overburden to coal ratio. Computers are used in: optimisation of pit design, improvement of shotfiring results, and formulating a work schedule specially adapted to market requirements. 885394 Engineering geological problems in construction of underground structures in urban areas of Belgrade Lokin, P; Pavlovic, N; Bogdanovic, A; Mijajlovic, R Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 20-25 October 1986 I/3, P1877-1885. Publ Rotterdam: A A Balkema, 1986 More and more underground structures are being built in Belgrade. The geotechnical structure of the relevant soil and rock mass, basically loess over a weathered zone then fresh marls and clays, is first described. Basic engineering geological problems arising in rock mass excavation, stability of underground structures and their lining and support, construction through the weathered zone and at unstable slopes, and surface subsidence and settlement over tunnels during construction are then discussed.

Stresses around underground openings 885395 Quadratic variation indirect boundary element method for traction boundary-value problems of two-dimensional elastostatics Jiali Lu; Watson, J O int J Num Anal Meth Geomech VI2, N2, March-April 1988, P183-196 Two-dimensional plane strain and plane stress problems related to excavation sequences are studied using the indirect boundary element method. Quadratic variation functions for the representation of geometry, ficticious forces, and displacements over each boundary are described. Stress and displacement analysis around underground excavations is used to demonstrate the accuracy and efficiency of the formulation illustrated. 885396 Tracing of sliding lines in media with planes of weakness and stability analysis of underground rooms Hudec, M; Frgic, L Proc 6th International Congress on Rock Mechanics, Montreal, 30 Aug-10 Sept 1987 V2, P975-979. Publ Rotterdam: A A Balkema, 1987 Computer stress analysis of jointed rocks around underground structures can be used to predict slip lines and joint planes where sliding will occur. Stress fields are calculated using elasticity theory. A Mohr-Coulomb failure criterion is assumed.

1988 Pergamon Press plc. Reproduction not permitted