1. The Wiental Sewer is part of a
large environmental project
that will increase considerably
the water quality of the rivers
around Vienna. After heavy
rainfall, the existing sewers of
the city reach their capacity
limits and the water, a mixture
of rainwater and wastewater,
overflows the sewerage sys-
tem and pollutes the rivers.
The new Wiental Sewer with a
diameter of 7.5 m and a
length of 2,690 m will not only
be able to drain rain and
wastewater, but also to store
110,000 m³ of it during rainfall
and discharge it afterwards in
a controlled manner into the
main wastewater treatment
plant of the town.
The Wiental Sewer will run
beneath the city of Vienna at a
depth of about 35 m and will
passes underneath the Wien
River as well as an under-
ground railway line at a dis-
tance of only 3 m. Along its
way, eight shafts with a depth
of up to 40 m each will be
installed.
The soil conditions in the area
consist of tertiary silts, sands
and clays. Over its whole
length, the tunnel will be
excavated below ground
water level which is up to 20
m above the future tunnel
crest.
For the excavation of the
sewer, a tunnel boring ma-
chine (TBM) with a diameter
of 8.60 m equipped with an
earth-pressure balance shield
will be employed. The TBM
has a jacking force of 6,400
tonnes and a driving power of
the cutter wheel of 2,000 kW.
Including its back-up system,
the TBM is 135 m long and
weighs 1,090 tonnes. The
tunnel will be lined with 1.50
m long concrete segments
and sealing gaskets. The
anticipated average driving
progress is 20 m per day.
The eight shafts along the
sewer which are up to 40 m
deep will be built by means of
diaphragm walls or secant
pile walls with pile diameters
of 2 m.
Wiental Sewer,
Vienna, Austria
Contract Value:
USD (m) 67.5
Construction Period:
03/2004 – 03/2006
Client:
Magistrat der Stadt Wien
(Vienna City Council)
Services:
Construction of a main
sewer with an excavated
diameter of 8.60 m
Reg.14-bb-100-bb-0-020-00