Shotcrete: No miracle worker, but a good support in tunneling

Shotcrete: No miracle worker, but a good support in tunneling

153A environment are Iresented. An historical review of US regulations governing subsidence-related Iroblems is given, and new regulations being deve...

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environment are Iresented. An historical review of US regulations governing subsidence-related Iroblems is given, and new regulations being developed under the cm~rent regulatory refcmun programme are discussed. 835177 EXTENDED RANGE OF DmI'aMMINATION OF THE PREDICTED EFFECTS OF UNDERGROUND MINTN~ FOR THE PURPOSE OF SURFACE PROTECTION Szpetkowskl, S Arch Gorn, V27, N1-2, 1982, PB-32 Discusses: (i) determination of deformation at particular surface points, (2) determination of the cumulative effect of mining several seams and (3) relresentation of the calculated results in graphs ard diagrams. 835178 GROUND S E ! ~ S FRC~ THE EXCAVATION OF TUNNELS IN SOFT CLAY Rodriguez, L B; Ruelas, S A In: Soft-Groumd Tunneling, I~7-6~. Publ Rotterdam: A. A. Balkmna, 1981 Presents measurements of short-term ground surface movements resulting from shleld-driven sewer tummels in soft volcanic clays underlying Mexico City. Predictions of soil settlements were foumd to be aPlrOxinmtely 30 per cent larger than recorded values. 835179 LOST-GROUND SUBS]S3ENCES IN TWO ~ 0 ; TUNNELS Sowers, G F In: Soft-Grourd Tunneling, P75-78. Publ Rotterdam: A. A. Balke~a, 1981 Two shallow liner-plate tunnels in mleaceous sandy silt residual soils caused significant subsidence at the grotmd surface. There were two factors in ccmnon: (i) the groundwater level initially was near the centre of the bc~e, amd (2) excessive overexcavation at the tunnel face without l ~ n p t filling of the void between the liner plate and the ground. Iml~rovedworkmanship reduced the subsidence to tolerable amounts in both cases.

Temporary and permanent supports 83518o STAINLESS

~r ~.'~.'L REINFORCES D ~ B Y SEWERS Dadson, J New Civ E n ~ , N546, 23 June 1983, P30-31

Fibre slrayed concrete, a mix of cement, sand and stainless steel flbres, is being applied as a lining in the refurbishment of the sewers in Derby, Derbyshire, UK. 835181 LATTICE GIRDERS ~ ECONOMY AND PERFORMANCE FOR TUNNEL SUPPORT Braun, W M Tunn Turmlg, V15, N'3, May 1983, P19-21 Lattice girders are grad,n]ly replacing collierytype steel arches in tunnel support and lining systems. These novel tunnel supports also allow strengthening of the system with additional steel bars and are perfectly suited to the subsequent application of tunnel lining concrete, as in the New Austrian Tunnelling Method. 835182 'MAGIC' INGReDIEnT UR3RADES SHOTCRETE AND CONCRETE FOR TUNNELS Martin, D Turn Tunnlg, V15, ~ , April 1983, ~ 8

Microsilica is beimg used to improve the strength axrl durability of concrete anl to increase resistance to water penetration. 835183 SHOTCRETE: NO MIRACLE WORKER, BUT A GOC~ SV2FORT IN TUNNELING Framzen, T Umiergroumd Space, V7, N3, Nov 1982-Jan 1983, P150-151 Report on the ~th Engineering F ~ t i o n Conference on Shotcrete for Underground Sta'uctural Support, Paipa, Boyaca, Colombia, September 1982. 83518~ ROOF SUPPORT S Y ~ FOR SEAMS OVER 5 METRES Bewick, D Min Engr, V142, N258, March 1963, P507-511 Examines mining systems that used powered support technology s_nd which have been developed for extracting thick seams, with special refe r e m e to the sublevel caving system. 835185 BEHAVIOUR OF CSm~mV~ND TAILINGS SANDS Mitchell, R J; Wong, B C Can Geoteeh J, Vlg, N3, Aug 1982 , P289-295 Bulk pours of cemented taili~gs sands are used as groumd control backfill in umderground mines. Unconfined compression tests were perfc~ned to try and relate factors such as cement content, pour pulp density, porosity and curing ht~nidity to backfill stremgth. Unconfined stremgth was fourd to increase with increased cement content, i n c r e a s e d pulp density, decreased porosity and decreased curing humidity. Data from triaxial compression tests indicated a relation between unconfined strength and the failure envmlope from the triaxial data. Either strength may be used in the design of backfill. 835186 SUPPORT IN SHAIIDW MINES USING HORIZONTALLY RETNFC~CED Hahn, J A; Blight, G E; Dison, L J S Afr Inst Min Metall, V82, NIO, Oct 1982,

~77-29o In shallow mines, replacement of pillars with artificial supped'is would allow complete extraction af the seam being mimed. The paper ~roposes a s y s t e m o f stt~pcrt using horlzo~tally reinforced materials (grarAtlar or cemented materials) in which t h e suppm~ system can be accurately d e s i g n e d to accept a p r e d e t e r m i r ~ load.

Construction methods 835187 F I ~ B A ~ FOR WIGAN SOMP Hayward, D New Civ Engr, N~2, 26 May 1983, P20-21 24m long sheet piles are being used to form a permanent cofferdam and walls for Lately Co,non pump station, Wigan, Lancashirej UK. The urgerground pump station, part of a new sewage network, is sited on an alluvial flood plain with 28m of sands and silts overlying bunte~r samdstone. Local mining subsidence required the inherent flexibility of a permanent sheet piled structure.


~-l~OD FOR TRAMWAY TUNNEL IN ZURICH Andraskay, E; Ramer, E; Berger, E Rock Mech Rock Engng, VI6, N1, Feb 1983,