Jacked tunnel, Boston Central Artery
projectMott MacDonald has gained extensive expertise in this
specialist tunnelling technique over the last 20 years. Tunnel
jacking was first used in the UK in the 1960’s as a development of
pipe jacking, when increased circular pipe sections became too
large to easily manoeuvre into thrust pits. The technique has
evolved from moderately sized sections, jacked in modules to form
bridge abutments, to monolithic rectangular tunnel sections to
allow passage of three lane highways beneath railroads, highways,
rivers and airport runways. Tunnel jacking often provides the only
practical solution to achieving a shallow tunnel beneath a facility
without significantly affecting its operation.
We've been involved in all aspects of development and innovation
associated with tunnel jacking, undertaking projects from
pedestrian subway boxes to multi-stacked jacked units forming
bridge abutments and full sized highway jacked tunnel boxes. Often
these projects have required tunnel installation beneath major
facilities such as multi-track mainline railways, highways and
airport runways. Tunnel jacking requires close co-ordination
between designers and contractors, including careful monitoring of
ground movement effects during installation. Mott MacDonald has
also developed instrumentation data collection and reporting tools
to enable effective monitoring and control of ground movements to
manage risk during construction.
Thrust pit for ramp D jacked tunnel, Boston
Central Artery ProjectMott MacDonald was appointed as
the designer for three highway jacked tunnel structures passing
beneath mainline tracks at Boston South Station. This work forms
part of the $10.8 billion Boston Central Artery Project. The
tunnels, at 11m high are up to 24m wide and 115m long, represent
one of the largest and complex jacking installations ever
undertaken. We are also project manager for the development of a
highway tunnel to be jacked beneath the M1 motorway. This will be
the first application of the technique of this scale under a major
highway in the UK.
Examples of other jacked box projects include:
- Jacked abutments to Poplars Railway Bridge, UK
- Fawdon Railway Bridge, Newcastle, UK
- Jacana Underpass, Melbourne, Australia
- Sungshan Airport Highway Tunnel, Taiwan
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