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| case history |
| Stabilization of a road embankment
on very soft marine silts and clay, for the Beheith Military
Road Project, Kuwait |
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| PRODUCT |
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TENAX LBO 220 SAMP,
TENAX LBO 440 SAMP
TENAX LBO 270 SAMP |
| LOCATION |
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Beiheith Kuwait 2001-2002 |
| OWNER |
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State of Kuwait Ministry of Defence |
MAIN ROAD
PROJECT DESIGNER |
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State of Kuwait Ministry of Defence, Military
Eng. Projects |
CAUSEWAY
PROJECT DESIGNER |
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Tenax Spa Technical Office
Milan Italy |
| CONTRACTOR |
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Bander & Faisal Al Masoud
Kuwait |
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problem
To enable The Ministry of Defence of The State of Kuwait to
construct and operate a new coastguard station on the coast
of northern Kuwait a road and causeway had to be constructed
over very soft marine silts and clay, with CBR values of less
that 0.5 this proved to be a challenging exercise both in
terms of design and installation techniques.
Whenever a paved
or unpaved road needs to be built on soft or saturated soil,
settlement may take place during or after construction, with
serious consequences for the life span of the road.
The base layer, made-up from granular material, can sink into
the foundation soil, and horizontal and vertical movement
capable of forming ruts can occur at the base.
To avoid these
phenomena, it's necessary to place one or more layers of reinforcing
geogrids having the ability to confine the aggregate and distribute
the load.
The project was split into four separate areas:
the main 9 km long access road; a man made island that would
be used for the construction of the coastguard station; a
550 m long causeway linking the coastguard station with an
offshore jetty and the installation of gabion mattresses on
the shoulders of the slopes in the tidal areas.
solution
The design carried out by Ministry of Defence Military Engineering
Projects team required the inclusion of 1 layer of a 40 kNm
x 40 kNm integral geogrid and one layer of a 20 kNm x 20 kNm
integral geogrid in non tidal areas. In areas that would be
affected both by high tides and the very low bearing capacity
of the underlying soil conditions (CBR less than 2.0) two
layers of the 40 kNm geogrid and one layer of the 20 kNm geogrid
would be installed.
The contractor proposed TENAX LBO 440 SAMP and TENAX LBO 220
SAMP geogrids as being products that met the requirements
of the design specification and the Ministry of Defence design
team duly approved their use.
The man made island that would
form the coastguard station and working area was constructed
using 2 layers of TENAX LBO 440 SAMP geogrids and one layer
of TENAX LBO 220 SAMP geogrid.
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The contractor was responsible for the design and construction of the 550 m long causeway; the design was carried out on behalf of the contractor by the technical design office of TENAX SpA using the latest design software.
The 550 m long causeway,
the height of which ranged from 1.7 m to 3.0 m, was to connect the
man made island with the offshore jetty, the design allowed for
settlement to take place during the construction phase to afford
a stable roadway to enable the coastguard to access the jetty at
all times. Due to the very low bearing capacity of the foundation
soil it was clear during the construction of both the road, the
man made island and the causeway that it would have been impossible
to install either woven geogrids or geotextiles.
The gabion mattresses
for the shoulders and side slopes were constructed from TENAX LBO
270 SAMP geogrids and installed in the tidal areas to help eliminate
the erosive tidal effects that would occur in these areas. In all
some 400,000 m2 of various grades of
TENAX geogrids were installed.
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conclusions
The Kuwaiti Ministry of Defence design team and the contractor were
pleased with both the efficiency of the product and the technical
service supplied by TENAX. Including TENAX LBO 440 SAMP geogrids,
TENAX LBO 220 SAMP geogrids within the tidal area 9 km road with
low CBR values, the man made island and the causeway and TENAX LBO
270 SAMP geogrids for the gabion mattresses allowed the engineers
to:
- Increase the bearing capacity of the subgrade;
- Decrease the required thickness of the imported fill material
without reduction in long term performances;
- A reduction in construction time due to the ease of installation
of TENAX LBO SAMP geogrids;
- A reduction in cost due to the savings incurred in the reduction
of the special fill material;
- Construct a road in an area that would normally be inaccessible
to vehicles;
- Eliminate the erosive effect of the tidal flow on the embankments.
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geo@tenax.net