Cast blasting at Teck Corporation's Bullmoose Mine

258A 924407 Parametric study of steady state seepage into excavations Urzua, A; Christian, J T; Chang, S Ground Engng V24, NIO, Dec 1991, P24-32 Straightforward application of results from the theory of potential flow allows development of a method to plot both equipotentials and stream functions for the finite element analysis solution for steady state seepage into an excavation. The flow net can be developed for complicated flow problems if required. The solution to the classical problem is presented here, and the effects of key parameters on flow nets illustrated graphically. The parameters examined include sheet pile penetration, boundary conditions, anisotropy of the soil, presence of permeable or impermeable layers at excavation depth or below, excavation width, and presence of underlying aquifers.

924408 Free boundary, fluid flow, and seepage forces in excavations Borja, R I J Geotech Engng Div ASCE VII& NI, Jan 1992, P125-146 A finite element model (DIG-DIRT) has been developed to simulate the influence of fluid flow on the behaviour of braced or unbraced excavations. The material properties are dominant, but the combined effect of material loss and fluid flow tends to create a zone of intense yielding and plastic flow at the corner base. If free boundaries are created, effective stress near the wall is increased, and vertical consolidation results.

924409 Study of different aspects of diaphragm walls El Hussieny, O M Tunnlg Underground Space Technoi V7. NI. 1992, P55-58 Three aspects of diaphragm walls are assessed: basic requirements of trenching tools and tolerances for cast in place concrete walls; the role of the bentonite slurries used and their control; and diaphragm walls compared to piles as structural elements. The first considers the available types of trenching tool, deviations of the trench face, and their causes and control. The second examines effects of slurry properties on required functions, excavation support and sealing, and displacement by concrete. Finally, the end and side bearing capacities are examined for various geometries of diaphragm wall load bearing element.

924410 Subway tunnels with multiple functions in the Balcescu Boulevard, Bucharest Calinescu, S; Pisoi, G; Wintze, A Proc Ninth Danube-European Conference on Soil Mechanics and Foundation Engineering, Budapest, 2-5 October 1990 P303-306. Publ Budapest: Akademiai Kiado, 1990 Ground conditions in Bucharest are predominantly layered alluvial sands, clays, and silty clays, with water table at depth 3.5-7m. Construction of a shallow tunnel section in the central area where damage to historic structures could not be tolerated is described. The rectangular section tunnel was constructed by the cut and cover method between slurry walls. Problems arising with sealing joints in the slurry wall panels and due to underground utilities, and their solutions, are described. Carefully monitored surface settlements were within allowable limits.

924411 Influence of sinking underground structures or foundations by the caisson method on the surrounding ground mass and neighboring buildings Dachowski, R Proc Ninth Danube-European Conference on Soil Mechanics and Foundation Engineering, Budapest, 2-5 October 1990 P313-318. Publ Budapest: Akademiai Kiado, 1990 Ground movement as a result of caisson sinking is examined with reference to a 40m diameter, 13.1m deep caisson in saturated sandy clay and clayey sand. It was sunk gravitationally from an initial cut. Cracks in the ground, settlement, and caisson tilt were monitored during sinking. The main causes of ground movement were friction forces, caisson tilt, lowering of water table and outflow of thixotropic suspended material. Conditions for safe caisson sinking and protection of existing structures are discussed.

Construction methods 924412 Design and construction of the basement of The Galleries Shopping Centre, Bristol Peattie, G C; Mojabi, M S lnst Civ Engrs Proc V90, Ptl, Dec 1991, P1225-1253 Construction of a very large, 6m deep basement is described. Site conditions were unfavourable, fill and alluvial flood plain deposits over Keuper sandstone, with high groundwater levels. Over 100 existing piles required removal before the project itself commenced. A 400m long diaphragm wall cut 4m into rock was first constructed using conventional methods. Within this 120 base grouted large diameter piles with steel stanchions were constructed to carry the floor slab. Simultaneous basement excavation and superstructure erection followed. The construction method and sequence of operations are an integral part of the overall design process. 924413 Cast blasting at Teck Corporation's Bullmoose Mine Hallbauer, R E Proc 2nd International Symposium on Mine Planning and Equipment Selection,Calgary, 7-9 November 1990 P475-480. Publ Rotterdam: A A Balkema, 1990 Adoption of cast blasting is one of the many recent developments to improve economics of open pit mines. It has been widely used in dragline operations, but seldom with truck/shovel operations such as applied at the Bullmoose Mine, British Columbia. Mine design prior to use of cast blasting, the test and production cast blast design, and results of cast blasting are described. Productivity increase is largely because of shortened haulage routes, and corresponding reduction in plant running costs.

Groundwater problems 924414 Modelling of the functions of a refuse tip: hydrodynamics characterization and the investigation of what becomes of heavy metals in a typical refuse tip (In French) Legret, M; Raimbault, G Bull Liaison Labs Pants Chaussees N175, Sept-Oct 1991, P77-91 An experimental column, 2.7m high by 0.4m diameter, was used to simulate a typical waste tip and allow study of its hydrodynamics. Retention curves and relations between

,© 1992 Pergamon Press Ltd. Reproduction not permitted