 |
| Project
Title |
Athens Metro |
| Client |
SOGEA Attiko Metro A.E.
& Olympic Metro Public Works [MOC] |
| Main Contractor |
Olympic Metro |
| Featured
Products |
Weldgrip Gripforce
® Rockbolts |
|
 |
The Athens Metro construction project is one of the
largest and most complex in Europe. The project was managed by Attiko Metro
A.E. with a consortium of 25 Greek, German and French companies as the main
contractors, known as Olympic Metro. The Metro,
with a construction cost in excess of 2.2 billion ECU, consists of 2 lines
and 21 stations and will serve approximately 140,000,000 passengers annually.
Two 9.5m diameter tunnel-boring machines (TBM's) were
used to construct 11.7 km of tunnel, a further 2.5 km being excavated
by cut and cover methods.
The New Austrian Tunnelling Method (NATM) was used primarily
for the station galleries, subways and access ways. The geology of the
tunnels was mainly heterogeneous fractured schist. There were also occurrences
of limestone and peridotite. Due to the nature of the strata additional
support was required in the roof, tunnel sides and floor.
Fibregrip ® 22mm
and 32mm fibreglass rockbolts were used for both permanent and temporary
support in these areas. In areas of the roof where the strata was fractured
32mm and 22mm bolts 12m long were installed forward at the face of the
drivage before being excavated by the TBM.
In the areas where the station cross cuts thirled into
the main drivage the tunnel sides were reinforced by 22mm diameter Fibregrip
® rockbolts. Due to the ingress of water, particularly in the areas
of the tunnel where the limestone contained porous limestone deposits,
floor heave caused problems. This was overcome by floor bolting using
22mm diameter Fibregrip ® bolts. These could be easily cut out when
the floor was regraded. The Fibregrip ®
rockbolts used in this project were a polyester glass fibre bars with
tensile strengths of 470kN and 820kN and 275kN.
All bolts were installed into pre-drilled holes
filled with OPC grout.
The advantages found in using the rockbolts were: -
- Ease of installation due to the products light weight.
- The bolts are easily cut out by the TBM's without
damaging the machine's cutting heads.
- Bolts that have been partially cut out continue to
provide reinforcement.
- The high tensile strengths of the Fibregrip
® bolts provide excellent reinforcement in the Limestone and Schist
strata beds.
| |
If you would like to print this case study you can download the
full printable brochure in PDF format.
You will need Adobe Acrobat Reader to view and print the brochure,
if you need to download a free version of Acrobat Reader please
click
here.
|
|
- 620k |
 |
|
Weldgrip are also proud to have attained
BBA accreditation and ISO 9001 standards in recognition of our continuing
excellence in Geotechnical products and services. |
|
|
