Grand Paris Express grand debut for tunnel
boring machine Florence
Officially named on 18 September at Bonneuil-en-
France, Florence is the first tunnel boring machine
on Line 17, which will link Saint-Denis Pleyel to
Mesnil-Amelot.
Its mission is to bore a 3.4 km tunnel from the
Flandres shaft to the Rolland structure at Le Bourget.
Florence’s inauguration brought the number of tunnel
boring machines named since the start of the project
to 20, a symbolic figure that reflects the increasing
pace of work despite the Covid-19 crisis.
A spectacular operation
However, before entering the Île-de-France
underworld, Florence first had to endure its maiden
flight. Unlike the other Grand Paris Express tunnel
boring machines, which were assembled at the
bottom of the starting shaft, Florence was assembled
entirely above ground. The machine was then
lifted and manoeuvred towards the shaft before
being lowered down it. A gantry crane that can lift up
to 1,200 tonnes was required for this spectacular
operation.
Using Big Lift to lift the tunnel boring machine was a real technical challenge. The gantry crane can lift up to 1,200 tonnes.
Florence A tunnel boring machine in mid-air
“This imposing structure, known as Big Lift, can
be likened to a lift capable of carrying 15,000 people,”
explains Julien Sauvalle, Line 17 deputy project
director at Société du Grand Paris.
“Before being lowered to the bottom of the shaft,
the tunnel boring machine was separated into three
large sections. The shield and cutterhead were lifted as
a single block weighing 980 tonnes, a weight that a
conventional crane cannot handle. The first trailer
section followed, then the hood.”
When carrying a heavy load, the gantry crane moves
at a speed of six to seven metres per hour. “It took
12 hours to lift each piece and move it until it was directly
over the shaft. “Lowering each piece took a further five
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IDENTITY
2020 ACTIVITY
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