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A tunnelling project that bored 40m under the sea floor, for a distance of 38km, would undoubtedly present an epic challenge. Back in 1988, the Channel Tunnel project was to become the starting point for Bennett Associates' journey into the world of tunnelling. Over the past 20 years, they have developed an extensive experience and wide range of capabilities within the worldwide tunnelling industry.
Working alongside clients, contractors and manufacturers, they
have been involved with some of the world’s largest tunnelling projects
including the Channel Tunnel, Channel Tunnel Rail Link, Hong Kong Underground,
Storebaelt Tunnel in Denmark, the Heathrow Express and most recently, major
projects in Asia. Their expertise, innovation and flexibility has enabled them
to provide practical, cost effective solutions to a broad spectrum of tunnelling
problems.
Channel Tunnel
At 50 km (of which 38km is undersea), the Channel Tunnel is a feat of modern
engineering and has been declared by The American Society of Civil Engineers to
be one of the Seven Wonders of the Modern World. Bennett Associates designed and
produced detailed manufacturing drawings for the 235m long back-up system to the
Tunnel Boring Machine (TBM) for the Channel Tunnel, the world’s largest undersea
tunnelling project. They were also responsible for carrying out a full stress
analysis of the cutter head support, TBM structure and gripper body and pads
which was done by Finite Element analysis using ANSYS software solid modelling
elements. The analysis was used interactively by the Robbins designers in
Seattle USA. Close co-operation was maintained by visits to Seattle and exchange
of AutoCAD drawings to ensure that the complex interface between TBM and its
back-up system was correctly engineered.
TBM and backup design
Bennett Associates understand the complexities and potential problems that can
challenge tunnelling projects. Their knowledge and flexibility can provide cost
effective, reliable solutions that will keep the Tunnel Boring Machines on
schedule throughout the project. Through their experience and knowledge of
Tunnel Boring Machines and backup design, whether drilling through hard rock,
clay or a combination of materials, Bennett’s expertise can provide detailed
design solutions and complete integration of tunnelling systems for all ground
conditions. Their reference list includes the following machine types:
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Hard Rock |
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Earth Pressure Balance Machine (EPBM) |
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Clay |
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Slurry |
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Universal/Combination |
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Excavator |
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Hand Shields |
Materials Handling
Bennett Associates have a worldwide reputation for providing materials handling
solutions as part of the backup system. Bulk material handling systems design
expertise, principally gained from coal handling, stacking and reclaiming plant
allied to the power industry, encompasses production of plant layout and
detailed layout/manufacturing drawings. Their experience includes:
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Muck Conveyors |
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Segment Conveyors, Erectors & Handling |
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Screw Conveyors |
Conversions
Tunnel Boring Machines are extremely costly pieces of
machinery. Specified exactly to meet the requirements of one project, machines
can often become redundant following the completion of a tunnelling project.
Bennett’s experience and knowledge has enabled them to offer a conversion
service whereby existing redundant plant is checked, surveyed, re-configured and
re-designed for use on new tunnel contracts.
Infrastructure
Bennett Associates are well placed to offer effective design solutions to the
other infrastructure and support systems necessary to keep tunnelling projects
on track. These include Shaft Systems, Pipe Jacking and Handling, Airlocks,
Crossovers and Bulkhead Doors together with safety and environmental solutions
adapted to specific project requirements.
Their reputation for mechanical engineering design, coupled with
their rapid response and solution finding capability, was put to good use by
North West Water Ltd’s Fylde Coastal Water Improvement Scheme. AMEC Tunnelling
had been experiencing difficulties sinking shafts under balanced head conditions
through hard clay. A design was produced which incorporated new equipment
working in combination with AMEC's existing spoil removal shaft grab
arrangements. Following a six week development and detailed design period,
manufacturing was carried out within eight working weeks of order placement on
the suppliers.
Bennett’s diverse infrastructure experience also includes
designing two 26 metre sliding crossover doors for the Tai Lam tunnel train
track in Kowloon, Hong Kong, including the mechanism to close the 45 tonne doors
to provide a 4 hour fire barrier. The door system consists of two sliding leaves
each approximately 27 metres long and nearly 6 metres high. Each leaf weighs 45
tonnes. They move on two wheels housed in easy-access wheel boxes which run on
rails recessed in the concrete floor underneath and fixed in grout. When the
door is closed it is lowered to produce a structural gap between door and floor
of only 10mm.
Tunnelling within the confines of a built up area can pose many
logistical problems. During the work on the passenger interchange tunnel at
Green Park Station for the Jubilee Line Extension, work was carried out around
the clock and stringent noise emission parameters were placed upon the
constructors by Westminster City Council. In order to reduce noise pollution
around the excavation of the access shaft, Bennett Associates designed an
‘Acoustic Shroud’ for main contractors Tarmac Construction Ltd.
Consultancy
Bennett Associates can advise on all aspects of tunnelling including machine
selection and specification, technical investigations and safety. Their
experience of drilling through a variety of materials means that they are able
to recommend cost effective, workable solutions. Bennett’s can be on hand to
advise their clients throughout the project, from initial concepts and designs,
through to site supervision and fault analysis. Consultancy services include:
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Machine Suitability |
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Safety/Systems |
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Technical Investigations |
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Fault Analysis |
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Project Management |
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Litigation/Expert Witness |
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3rd Party Checking |
Established over the last 20 years, Bennett Associates worldwide
reputation in the tunnelling industry is testament to their ability to provide
innovative, cost effective and reliable solutions for tunnelling projects at
every level.
February 2008
For more information on how Atkins Rotherham can
assist with your tunnelling project, please telephone 01709-373782
M G Bennett and Associates Ltd is now part of the  Group |
