NeW THYSSeNKRUPP QUaRTeR NOW OPeN FOR BUSINeSS

26 IN BRIeF
The stabilisation with TITAN 30/11 injection piles
counteracts the differential deformations in the problem
zones at transitions.
STABILISATION
MEASURES WITH
INJECTION PILES
TITaN injection pile
applications for
Deutsche Bahn:
• Foundation elements for DB
overhead line masts
• Reinforcing elements for
retaining walls/piers
• Noise barriers
• Tunnel nailing
• Embankment stabilisation
• Slope stabilisation
In addition to talking about the use of injection piles on
Deutsche Bahn AG projects for improving the permanent way
and reducing settlement of railway embankments, Dipl.-Ing.
Godehard Drees also explained the advantages of bridge
abutments in the form of sheet pile walls with knife-edge
bearing.
TITAN 30/11 injection piles can be used to improve the
permanent way and reduce the settlement of railway
embankments. Underbridges represent a new application
for injection piles. The transitions between earthworks and
underbridge structures are always problem zones because
of the different stiffnesses and deformations. Bodies of soil
are always much more willing to deform than the relatively
rigid bridge or tunnel structures. That results in differential
settlement which leads to inconsistencies in the railway
track. Such undesirable settlement becomes more and more
critical for train operations as the running speeds increase.
More repairs and maintenance are necessary.
One way of substantially reducing this settlement at the soilstructure
interface without impairing rail traffic is to stabilise
the subsoil with injection piles. This method has been carried
out in Spain with great success and has proved itself as a
technique for improving the permanent way. Depending on the
size of the embankment, between 15 and 20 injection piles
are installed in the wedge-shaped transition zone in 2–4
layers, some 2–3 m apart. The injection piles can considerably
reduce the tamping processes necessary in the track.
Summary: Trains can travel faster and the costs of repairs and
maintenance are lower. An innovative, simple method for
improving the permanent way and allowing trains to run faster.
How TITaN injection piles work
Steel tendons in individual lengths of max. 3 m are screwed
together and drilled into the ground to the required depth
with the help of a flushing fluid, which stabilises the hole.
Pressure grouting begins once the design depth has been
reached. The drill rotates without drilling deeper and the
pressure grouting begins. During the pressure grouting, the
flushing fluid, which supports the sides of the hole, is replaced
by the stiff grout suspension (w/c ratio ~ 0.8 at 5–20 bar).
After it has cured, the body of injected grout together with the
soil reaches a final strength corresponding to concrete grade
B 25 at least.
IN BRIeF 27
Settlement in the wedge-shaped
transition zone can be kept in check
by means of injection piles.