herrenknecht ag softground tbms > 40 ft - SCATnow

process. The second trailer is a bridge construction to
allow free space of ±20 m for placing the road elements,
which are precast concrete parts of 2 m length
in dimension, 4.30 m in width and 4.56 m in height.
Each element has a weight of approx. 35 tons.
Supplies will be delivered to the TBM with trucks.
They will drive along these rectangular road elements
which are placed along the centre of the bottom of
the tunnel. The trucks will be unloaded in the back-up
trailer number 3.
Back-up number 1 will run on invert slabs. These
are placed on the already built segment ring and will
be taken out and moved to the front as soon as the
first back-up trailer passed this section. Back-up trailer
number three runs on auxiliary rails.
The tunnel excavation for the about 7,170 m per tunnel
tube is expected to take about 34 months. The commissioning
of the BOT-tunnels is planned for 2010.
near Shanghai and the inner-city tunnelling for the
M30 project in Madrid. Both projects illustrate the
feasibility of large diameter tunnels and are pointing
the way for future projects regarding the excavation of
even larger tunnel cross sections, long-distance bored
tunnels and even deeper excavations.
In general, it is important to have a good understanding
of all the conditions of a project already in
the planning stage. The geological information is of
particular interest because the machine design will be
adapted to the predicted geological conditions. It is
increasingly important to avoid possible risks when
tunnelling in urban areas and also in the open country
when underpassing existing structures or rivers and to
further adapt the technology to make it even more safe
and efficient.
4 CONCLUSION
The two cited Shield TBM projects are characteristic
of demanding conditions like the under river crossing
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