201A

these results, correction factors are provided to account for near face effects if a simplified two dimensional approach is used. Effects of anisotropy are discussed.

933476 Use of slurry-transport machines in the Ruhr mining_ district Steinbock, W Proc 2rot Internntimml SympoMum on Microtannelling, Manich, 8 April, 1992 P41-46. Publ Rotterdam: A A Balkema, 1992

Near-surface geology of the Ruhr district is variable, a tunnel- ling drive possibly passing through hard rock, weathered material, and loessial soils. Microtunnelling for a 2.3kin sewer collector, through crushed rock, gravelly ground, and landfill, is described. A slurry transport jacked machine with fully automated laser guidance was selected. The machine and its performance are discussed. The use of microtunnelling in the installation of rectangular underpinning to protect a historic building against mining subsidence damage is also described.

933477 Microtmanelling the Western Interceptor Sewer - Phase V, Newcastle upon Tyne, England Hayes, N F Proc 2nd International Symposium on Microtannelling, Manich, 8 April, 1992 1'47-57. Publ Rotterdam: A A Balkema, 1992

The use of microtunnelling for a sewer through variable geol- ogy with coal measures rock overlain by glacial deposits and surficial alluvium is described. This is believed to be the first time this technique has been chosen for the entirety of a major project, rather than just used for short individual sections. Contractual preparation, selection of the slurry face machine, construction procedures, techniques, and problems are described. The success of the drive demonstrates rnicrotunnel- ling is a viable alternative to conventional techniques in rock and boulder clay.

933478 Mlerotuanelang projects in Berlin and the new German provinces Becker, W Proc 2nd Interutiomd Symposium on Microtuaneiling, Mmtch, 8 April, 1992 P59-65. Publ Rotterdam: A A Balkema, 1992

Microtunnelling is the solution for renovation or construction of small diameter tunnels with minimum disruption to the environment or surface activities. Three urban case studies are presented where advanced technology was successfully applied. The first is a lkm sewer in water-bearing thick organic deposits. The second describes replacement of existing stoneware pipework beneath Berlin. The third is the construc- tion of 470m of sewer at depth 5m, 3.5m below the water table. A slurry support face microtunnelling machine proved an excellent alternative to the use of compressed air.

933479 Balancing risk and innovation in underground construction Robbins, R J Proc TUNCON '92, Design a~! Construction of Tunnels, Mnseru, Lesotko, September 1992 P1-2. Publ Yeoville: South African National Council on Tunnelling, 1992

Underground construction projects are high cost, high risk undertakings, but there is the possibility of high returns. Where the ground conditions are not well defined at the plan- ning stage, overconservative designs are often adopted and contractual problems and arguments are often found. The

need for innovation in major projects is emphasised. Three projects are considered, the Channel Tunnel, the Chicago TARP, and a proposed deep Alpine tunnel. Problems possible with prototype development on the job and potential develop- ments in advance tunnelling technology and their applications are discussed.

933480 Possible fast track tannelllng method at depth Spearing, A J S Proe TUNCON "92, Design a~! Construction of Tmmels, Mnseru, Lesntlm, September 1992 P3-8. Publ Yeoville: South African National Council on Tunnelling, 1992

As South African gold mines become deeper, the tunnelling problems increase. Rapid and risk free tunnelling is essential for economic viability of these mines. Elliptical tunnels with the long axis horizontal are better able to handle high stress regimes than rectangular tunnels, and have been used in the Buffelsfontein Mine. The key to their success has been adop- tion of a post-splitting drilling pattern and simultaneous drill- ing of the face and for cable bolt supports, installed pre-blast, close to the face.

933481 Project management of the tunnelling contract for the Lesntho Highlands Water Project Wetter, C C Proc TUNCON '92, Design and Construction of Tunnels, Maseru, Lesotko, September 1992 P17-22. Publ Yeoville: South African National Council on Tunnelling, 1992

The LHWP phase IA (transfer tunnel and delivery tunnels) is being constructed under the supervision of a multinational joint-venture consortium, the Lesotho Highlands Project Con- tractors (LHPC). Their management philosophy is outlined. Unusual complications arise because of the remoteness of the site and industrial relations, training, and safety for a basically unskilled workforce. The presumed benefits from the central- ised management system adopted are discussed.

Power plants

933482 Hydro tapping at Meraker Darting, P Tram Tannlg V24, Nl l , Nov 1992, P17-20

The Meraker project requires 43km of tunnel, mainly through Cambrian and Ordovician metamorphic rocks with intrusions of very hard metagabbro. All the rock was classified as hard to very hard with drillability index of 32-60. Three excavation methods are being used: hand-held drill and blast (4.4%), jumbo drill and blast (58.6%), and TBM (37%). Little inter- mediate support is required. Comparative advantages of the construction methods for this project are briefly discussed.

933483 Geotechnical review and evaluation of the New Waddel Dam outlets work tunnels, Central Arizona Project McNearney, R L Proc 28th Symlmsium on Engineering Geology and Geotedmicai Engineering, Boise, 1-3 April 1992 P162-179. Publ Pocatelio: Idaho State University, 1992

Geotechnical analysis carried out for three proposed concrete- lined pressure tunnels of diameter about 6m to be driven through Tertiary andesite, tuff, and conglomerate is described. The rocks were classified as either good or fair according the CSIR system. Excavation method (drill and blast), excavation

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