Behind bars

Behind bars

UNDERGROUND EXCAVATIONS:GROUNDWATER elongation of the concentration plume in the streamwise or transverse direction. (from Authors) 955347 Biosphere...

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UNDERGROUND

EXCAVATIONS:GROUNDWATER

elongation of the concentration plume in the streamwise or transverse direction. (from Authors) 955347 Biosphere model for assessing doses from nuclear waste disposal R. Zach, B. D. Amiro, P. A. Davis, S. C. Sheppard & J. G. %;k;&c Science of Ihe Total Environment, 156(3), 1994, pp . The biosphere model, BIOTRAC, for predicting long term nuclide concentrations and radiological doses from Canada’s nuclear fuel waste disposal concept of a vault deep in plutonic rock of the Canadian Shield is presented. This generic, boreal zone biosphere model is based on scenario analysis and systems variability analysis using Monte Carlo simulation techniques. Sensitivity analysis indicates lz91 is by far the most important radionuclide. Results also show bedrock-well water leads to higher doses to man than lake water, but the former doses decrease with the size of the critical group. (from Authors) 955348 Waste disposal in rock R. Pusch, (Elsevier; Developments in Geotechnical Engineering, 76), ISBN (hardback) 0 444 89449 7, price Dfl 310.00 (IJS%177.25), 1994, 490 pp. index. This is an overview of all the important issues involved in selecting suitable sites, design and construction methods for preparing repositories for hazardous waste in crystalline rock. Most of the examples used refer to radioactive waste. The focus in on the preparation and performance of multibarrier systems of rock, waste containers and sealing components in a long-term perspective. Examples are provided from largescale field experiments conducted in the international Stripa Project. (from Publisher)

Underground construction methods

955349 Cost-reduction strategies for subway design and constructiOll

G. S. Brieley Jc R. D. Drake, Tunneiling & Underground Space Technology, 10(l), 1995, pp 31-35. This paper discusses new strategies for the design and construction of subway systems from the point of view of faster implementation and reduced cost. The four primary strategies involve underground vs. cut and cover construction, long tunnel drives, the physical, or at least, functional separation of the mezzanine and platform areas of the stations and the contrctual separation of the tunnelling and finish portions of the stations and tunnels. (Authors) 955350 Pitch back L. Russell, New Civil Engineer (NCE), 1114, 1995, pp 20-21. Describes construction of underground garage for military vehicles. The 2000 m2 reinforced concrete box structure will be under a historic cricket ground in London, UK. Roof loading is critical to the design since a 700 mm thick layer of topsoil is required for the turf to survive. The structure will be built on a 700 mm thick raft foundation on London clay. It is designed to be watertight. Specific waterproofing measures adopted are outlined. (J.M.McLaughlin) 955351 Chamber Slot P. Wheeler, Ground Engineering, 27(8), 1994, pp 19-20.

245A

Describes excavation of three underground chambers for the Val de Pusteria underground waste water treatment works in Italy. Plant will be sited in a 330 m long central gallery with two 400 m long flanking galleries. Waste water is fed by a 3.9 m diameter, 920 m long delivery tunnel. A pilot tunnel provided invaluable geological data and allowed geological mapping. Several poor rock areas were identified. Rock mass classifications and support structures are outlined. Swellex rock bolts and sprayed concrete provided support in the enlarged galleries. (J.M.McLaughlin)

955352 Behind bars A. Oliver, New Civil Engineer (NCE), 1112, 1995, pp 21-22. The use of compressed air tunnelhng to overcome difficulties encountered during the installation of the caisson shaft through the waterlogged Thanet Sands is described. The excavation was part of the Jubilee Line Extension project in London. Safety measures relating to compressed air tunnelling are outlined. (P.M.Taylor) 955353 Construction of tbe cooling water tunnels using immersed tube techniques G. 0. Barratt 8c M. J. V. Sheridan, Proceedings - ICE: Civil Engineering, lOS(Specia1 Issue l), 1995, pp 63-72. The paper describes the construction of the cooling water tunnels for the Central Electricity Generating Board (later Nuclear Electric plc) at Sizewell B Nuclear Power Station in Suffolk. Approximately 900 m of tunnel elements were precast at Teesside, launched, towed to Sizewell and lowered into a predredged trench to link up with tunnels constructed on the foreshore. (Authors) 955354 Floating factory A. A. Brudno & A. R. Lancellotti, 27(l), 1995, pp 28-30.

Tunnels & Tunnelling,

An innovative construction method for immersed tube tunnels is described. A submersible pontoon is used as a base for construction of the tube sections. The stages in construction and achieving flotation of the section are described in detail. As the sections are built in flotation, there is no requirement for a casting basin. This has significant cost and environmental advantages over conventional fabrication methods. (J.M.McLaughlin)

Groundwater problems

955355 Stollen im Bergwasaer: Prognose, Propbezeiung und Realitat der Auswirkungen (Tunnels of ground water: prediction, prophecy and actual consequences) S. Jacobs & E. Tentschert, Fefsbuu, 12(6), 1994, pp 466-473. Two examples are presented: Strassen-Amlach Hydro-powerplant (Eastern Tyrol, 3.9 m diam. TBM-driven pressure tunnel through dolomitic limestones, 1985 - 1987) and Koralim Hydro-power-plant (Carinthia, 3.5 m diam. TBMdriven tunnel through crystalline schists, 1988 - 1989). The hydrogeologic predictions are compared with the real conditions observed during construction and up to 1994. (English summary)