hours,” adds Nordine Lasri, tunnel boring works
manager at Demathieu Bard, lead firm of the
Avenir consortium, responsible for this operation.
“We had heard of Big Lift, which is widely used in many
seaports, but using it to lift the tunnel boring machine
was a real technical challenge. We were particularly
careful when lifting the shield because its weight was
not evenly distributed.”
Using this technique was only possible because the
worksite covered a particularly large area. It meant
that Florence could be assembled and put through
its dry runs at the same time as the shaft was being
completed. Reusing a tunnel boring machine that
had already worked on the southern section of Line 15
was also a key factor in considering this solution.
New lease of life for Steffie-Orbival
Florence has the unique distinction of being the
first reconditioned tunnel boring machine used on
the Grand Paris Express.
Then operating under the name of Steffie-Orbival,
this machine bored a 2,183-metre tunnel from
Champigny-sur-Marne to Villiers-sur-Marne
between March 2018 and October 2019. After it was
dismantled, most of its parts were stored at a site
in Thieux. “The most sensitive parts, such as those
associated with the bearing, were sent back to supplier
Herrenknecht in Germany to be overhauled or replaced.
“The body of the machine is reconditioned, but its
heart and internal organs are almost new,” says Lasri.
A second decompression chamber has also been
added to the tunnel borer to make maintenance
operations easier.
Once it has finished boring along its current route
in early 2022, Florence will be redeployed at Triangle
de Gonesse. From there, it will return to the
underworld to bore a portion of the Line 17 tunnel
back to the Flandres shaft, which will eventually be
used for emergency access and ventilation. This will
complete the loop.
Lowering tunnel boring machine Florence to the bottom of the Flandres
shaft after being assembled above ground.
CSR APPROACH
RISKS AND CHALLENGES
IDENTITY
2020 ACTIVITY
Activity report
